In the following questions, one part of the sentence may have an error. Find out which part of the sentence has an error and click the button corresponding to it. If the sentence is free from error, click the "No error" option.

The building collapsed(a)/at the afternoon (b)/at about 4 o'clock (c)/No Error(d).

A

The building collapsed

B

at the afternoon

C

at about 4 o'clock

D

No Error