Arrange the given words in the sequence in which they occur in a standard English dictionary: 1. Exacts 2. Exotic 3. Exactly 4. Exacerbate 5. Exhaust.

Introduction / Context:
This dictionary order question uses five words beginning with Exa, Exe or Exo: Exacts, Exotic, Exactly, Exacerbate and Exhaust. The task is to place them in the same order in which they would be listed in a dictionary. This requires careful comparison of letter sequences and a clear understanding of lexicographic rules, especially when the words share common prefixes.

Given Data / Assumptions:
- Words: 1. Exacts, 2. Exotic, 3. Exactly, 4. Exacerbate, 5. Exhaust.
- Standard alphabetical ordering is used.
- Case is ignored and only letter order matters.
- If one word is a prefix of another, the shorter one comes first.

Concept / Approach:
Begin by grouping words based on their first few letters. Here, Exacerbate starts with Exa c..., Exacts and Exactly start with Exa c t..., Exhaust starts with Exh..., and Exotic begins with Exo.... Comparing these groups by their distinct letters provides a high-level order. Then, we sort words within a group using detailed letter comparisons. This structured approach avoids confusion when similar looking words are involved.

Step-by-Step Solution:
Step 1: Note the initial letter patterns: Exacerbate (Exa...), Exacts (Exac...), Exactly (Exac...), Exhaust (Exh...), Exotic (Exo...). Step 2: Compare the second and third letters: all begin with Ex, so check the third letter: Exa (Exacerbate, Exacts, Exactly), Exh (Exhaust), Exo (Exotic). Step 3: Alphabetical order of the third letters is a, h, o, so the Exa group comes first, then Exhaust, then Exotic. Step 4: In the Exa group, compare Exacerbate with Exacts and Exactly. Exacerbate is Exa c e..., while Exacts and Exactly are Exa c t.... Step 5: After Exac, Exacerbate has e, while Exacts and Exactly have t. Since e comes before t, Exacerbate (4) is first in the Exa group. Step 6: Compare Exacts (1) and Exactly (3). They share Exac t. The next letters are s in Exacts and l in Exactly. Step 7: Because l comes before s, Exactly (3) comes before Exacts (1). Step 8: Among the remaining words, Exhaust (5) with Exh... comes before Exotic (2) with Exo... since h precedes o. Step 9: Putting everything together, the full dictionary order is: Exacerbate (4), Exactly (3), Exacts (1), Exhaust (5), Exotic (2) or 4, 3, 1, 5, 2.

Verification / Alternative check:
List the words as Exacerbate, Exactly, Exacts, Exhaust, Exotic and verify each adjacent comparison. Exa... forms precede Exh... and Exo... as a < h < o. Within Exa..., Exacerbate comes first because after Exac, e precedes t. Within the Exac t group, Exactly precedes Exacts because l precedes s. After that come Exhaust and Exotic in that order since h precedes o. Mapping this final list back to indices yields 43152, matching option A.

Why Other Options Are Wrong:
Option B (43251) misorders Exhaust and Exotic. Option C (53421) moves Exhaust to the front, which goes against the Exa versus Exh comparison. Option D (54312) and option E (45132) also break the consistent lexicographic sequences between the Exa, Exh and Exo groups. Only option A correctly captures every comparison step.

Common Pitfalls:
The main pitfall is to assume that Exacts must come before Exactly because it appears shorter or looks simpler, without doing a letter by letter comparison. Another trap is to ignore the Exa, Exh and Exo grouping and treat all words as if they share identical prefixes. Build the groups first, then refine the order inside each group to stay accurate.

Final Answer:
The correct dictionary order of the given words is encoded as 43152.