I am waiting . . . . . . . . my brother. A. on B. to C. for D. at

The correct answer is C. “for”.

“For” is used to indicate a period of time during which someone or something is expected or desired. In this case, the speaker is waiting for their brother, which means they are expecting him to arrive at some point.

The other options are not correct because they do not indicate a period of time. “On” is used to indicate a location, “to” is used to indicate a destination, and “at” is used to indicate a specific time.

Here are some examples of how “for” can be used in other sentences:

• I am waiting for my brother to arrive.
• I am waiting for the bus.
• I am waiting for the results of the test.