Arrange the given words in the sequence in which they would appear in a standard English dictionary: 1. Dillydallying 2. Dillydallied 3. Dillydally 4. Dilled 5. Dillydallies.

Introduction / Context:
This question explores dictionary order among several words that share a common root. All the words start with Dill but differ in their endings, such as Dilled, Dillydally, Dillydallied and so on. The candidate must decide which arrangement of indices reflects the order that would appear in a dictionary. This tests detailed familiarity with lexicographic comparison, especially when words share long prefixes but differ in later letters and word length.

Given Data / Assumptions:
- The words are: 1. Dillydallying, 2. Dillydallied, 3. Dillydally, 4. Dilled, 5. Dillydallies.
- Standard English dictionary order is followed, comparing letters from left to right.
- If one word is a complete prefix of another, the shorter word comes first.
- The spellings are accepted as they are for the purpose of ordering.

Concept / Approach:
When words share the same initial sequence, dictionary order is decided by the first letter where they differ. First, identify any word that diverges earlier, such as Dilled, which breaks away from the Dilly pattern. Among the Dilly variants, we must then compare position by position and finally apply the rule that shorter words come before longer ones if all preceding letters match. Doing this methodically gives the correct ordering without confusion.

Step-by-Step Solution:
Step 1: Observe that Dilled (4) has spelling D i l l e d, whereas the others begin D i l l y, so Dilled diverges at the fifth letter. Step 2: Compare Dilled with any Dilly word at the fifth letter: Dilled has e, while Dillydally and its variants have y. Since e comes before y, Dilled appears before all Dilly words. Step 3: Thus the first word in dictionary order is Dilled (4). Step 4: Consider only the Dilly words now: Dillydallying (1), Dillydallied (2), Dillydally (3), Dillydallies (5). All start with the same letters D i l l y d a l l, so we look beyond that common prefix. Step 5: Focus on their endings: Dally, Dallied, Dallies, Dallying. After Dillydall, we effectively compare y, i e d, i e s, y i n g. Step 6: For dictionary order, Dillydallied (2) comes before Dillydallies (5) because at the point of difference, e d comes before e s. Step 7: Dillydally (3) is the shortest and is a complete prefix of Dillydallying (1), so Dillydally (3) comes before Dillydallying (1). Step 8: Combining these, under the Dilly group the order is 2, 5, 3, 1. Step 9: Finally prefix the initial 4 for Dilled, giving the total order 4, 2, 5, 3, 1 which is 42531.

Verification / Alternative check:
To verify, write the words in the derived order: Dilled, Dillydallied, Dillydallies, Dillydally, Dillydallying and read through them as if on a dictionary page. Ensure that whenever you move from one word to the next, the next word is indeed later alphabetically. At each step, check the first differing letter or, if one word ends while another continues, confirm that the shorter word appears first. Doing this confirms that our sequence 42531 respects the dictionary ordering rules.

Why Other Options Are Wrong:
Option A (42351) incorrectly places Dillydallying before Dillydally. Option C (45312) and option D (45321) misplace Dilled among the Dilly words or mix up the internal order of the Dilly variants. Option E (41235) positions the words in a sequence that does not follow from careful letter by letter comparison. Only option B mirrors the correct lexical order.

Common Pitfalls:
A frequent mistake is to assume that longer words always come later, without checking whether one is a strict prefix of another. Another pitfall is losing track of indices when mapping between actual words and numbered options. Words sharing long prefixes can also cause confusion, leading to swaps between very similar endings. To avoid these issues, always perform a systematic comparison and then carefully convert the word sequence back to the numeric code shown in the answer choices.

Final Answer:
The correct sequence in dictionary order is represented by 42531, which corresponds to option B.