The experienced clerk found herself at … .

Analyze the question: The sentence uses an idiom, "at a crossroads," meaning at a point where an important decision must be made. The question tests knowledge of the correct form of this idiom.

Explain the concept: The word crossroads is used in the singular sense with the article "a" even though it ends in -s. The standard idiom is:

• at a crossroads (figurative: a critical decision point)

Dictionaries list crossroads as a word with the same form for singular and plural. So "a crossroads" is correct and accepted, whereas "a crossroad" is rarely used for this idiom, and "some crossroads" doesn't fit the idiom.

Step-by-step elimination:

• A. a crossroad: Not the standard form of the idiom. Wrong.
• B. some crossroads: "Some" makes it plural and loses the idiomatic meaning. Wrong.
• C. a crossroads: The correct idiomatic expression. ✔
• D. the crossroad: Wrong form and article; it does not fit the idiom.

Answer: The experienced clerk found herself at a crossroads, meaning she faced an important decision in her career or life.

Tip: Memorize fixed idioms as whole chunks: at a crossroads, at a loss, at a standstill. In the exam, don't try to "fix" the grammar of an idiom. Recall it as you learned it.