Select the most appropriate option to fill in the blank and make a grammatically correct sentence.

Simran was reading a book _____ waiting for the bus.

while

The most appropriate option to fill in the blank is while.

The word "while" is used to indicate that two actions are happening at the same time. This is the most appropriate word because it accurately describes how Simran was reading a book while she was waiting for the bus.

The other options are not as appropriate.

• From indicates a starting point. This does not make sense in the context of the sentence, because Simran was not reading a book from the time she started waiting for the bus.
• During indicates a period of time. This does not make sense in the context of the sentence, because Simran was not reading a book during the entire time she was waiting for the bus.
• At indicates a specific point in time. This does not make sense in the context of the sentence, because Simran was not reading a book at a specific point in time while she was waiting for the bus.