Question

Не started work ................. 9 am.

• A. in
• B. at
• C. for
• D. on

Answer 1

Answer:

B. at

👉 He started work at 9 a.m.

Explanation:

• At is used with exact points of time (clock time).

• 9 a.m. is a specific time.

Why the others are wrong:

• ❌ in – used with months/years/long periods

• ❌ for – used with duration

• ❌ on – used with days and dates