In the following question, a sentence is divided into four parts. Choose the part of the sentence which may contain a grammatical error in it. If all the parts of the sentence are grammatically correct and contextually meaningful, choose option “No error” as the answer choice.
She is (A)/ a dedicated officer (B)/ working in (C)/ an female unit. (D)

The correct answer is D.

Step-by-step Explanation:
Let us analyze each part of the sentence to identify the grammatical error:
1. "She is" (Part A): This is grammatically correct, matching the third-person singular pronoun "She" with the singular verb "is".
2. "a dedicated officer" (Part B): This is grammatically correct. The indefinite article "a" correctly precedes the adjective "dedicated" because "dedicated" starts with a consonant sound (/d/).
3. "working in" (Part C): This is grammatically correct, using the present participle verb form "working" followed by the preposition "in".
4. "an female unit." (Part D): This part contains a grammatical error. The word "female" begins with the consonant sound /f/. In English grammar, the indefinite article "a" must be used before words that start with a consonant sound, whereas "an" is reserved for words starting with a vowel sound. Therefore, "an female unit" should be corrected to "a female unit".

Thus, the grammatical error is in part D.