Question

Fill in the blank with a suitable preposition:
I'll call you ________ seven o'clock.

• A. In
• B. On
• C. At
• D. Of

Answer 1

The correct option is C At

Answer : C

Prepositions are words that indicate relationships with the other words in the sentence. Prepositions of time are used to denote time in a sentence.

Let's look at the usage of various alternatives in the option as preposition of time:

• at : to refer to an exact time of the day, also used along with "night"
• in : to refer to a period of time, usually years / months / seasons / morning / afternoon / evening
• on : to refer to days / period of time
• of : not generally used as a preposition of time but sometimes used to express time in relation to the following hour
  

In the question, a specific / exact period of time has been mentioned ("seven o'clock"). Therefore, the suitable preposition here is "at".

Thus, the correct complete sentence is:

I'll call you AT seven o'clock.