Arrange the following words in the same sequence in which they would appear in an English dictionary, and then select the correct code: i. Uniform ii. Unitary iii. Umbrella iv. Unicorn.

Introduction / Context:
This dictionary order question uses several words beginning with U N and U M. You must correctly order Umbrella, Unicorn, Uniform, and Unitary, which helps build precise alphabetical comparison skills often tested in reasoning sections of competitive exams.

Given Data / Assumptions:

• Words with codes: i. Uniform, ii. Unitary, iii. Umbrella, iv. Unicorn.
• We must arrange these words alphabetically as in an English dictionary.
• Standard alphabetical ordering is applied.

Concept / Approach:
The steps to determine dictionary order are:

• Compare the first letter of each word. If equal, compare the second letter, and so on.
• The first differing letter decides the relative order.
• If one word is a full prefix of another, the shorter word appears earlier.

Here, the second letter plays a key role, since Umbrella starts with Um and the others start with Un.

Step-by-Step Solution:
Step 1: List words clearly: Umbrella, Uniform, Unitary, Unicorn. Step 2: Compare first letters. All start with U, so we move to the second letter. Step 3: Second letters: Umbrella has M (Um), while Uniform, Unitary, and Unicorn have N (Un). Since M comes before N, Umbrella (iii) must be the first word in dictionary order. Step 4: Now focus on the Un words: Uniform (i), Unitary (ii), and Unicorn (iv). All start with U N I, so compare further letters. Step 5: After UNI, we have the following sequences: Unicorn has C O R N, Uniform has F O R M, and Unitary has T A R Y. So at the fourth letter after UNI (that is the letter just after UNI), we compare C, F, and T. In alphabetical order, C comes before F, which comes before T. Step 6: Thus among the Un words, Unicorn (iv) comes first, followed by Uniform (i), and then Unitary (ii). Combining with Umbrella as the first overall, the complete sequence is Umbrella (iii), Unicorn (iv), Uniform (i), Unitary (ii).

Verification / Alternative check:
You can verify the order by writing the words in full and sorting them visually: Umbrella, Unicorn, Uniform, Unitary. This sequence reads naturally in alphabetical order and matches the derived code iii, iv, i, ii.

Why Other Options Are Wrong:
Option iii, i, iv, ii places Uniform before Unicorn, ignoring that C in Unicorn comes before F in Uniform. Option iii, iv, ii, i puts Unitary before Uniform, even though F comes before T. Option iv, i, ii, iii incorrectly moves Umbrella to the end, although Um should come before any Un word. Option iv, ii, i, iii misplaces both the starting word and the relative positions of Uniform and Unitary.

Common Pitfalls:
Candidates may forget that the second letter can change order even if the first letter is the same, or they may rely on the length or familiarity of the word rather than strict letter comparison. Another pitfall is ignoring the fact that Umbrella begins with UM, which clearly should appear before UN words.

Final Answer:
The correct dictionary sequence is Umbrella, Unicorn, Uniform, Unitary, corresponding to the code iii, iv, i, ii.