Select the option that is the passive form of the given sentence.

The Principal gave her a warning about coming late to school every day.

A

She gives a warning to the Principal about coming late to school every day.

B

She has given a warning by the Principal about coming late to school every day.

C

She was given a warning about coming late to school every day by the Principal.

D

She was giving a warning by the Principal about coming late to school every day.