Select the option that expresses the following sentence in active voice.
The pizza was ordered by Nikita at 5 p.m.

Correct option is B

The correct active voice expression is (b) "Nikita ordered the pizza at 5 p.m."
The passive voice "The pizza was ordered by Nikita at 5 p.m." is directly converted to active voice by making Nikita the subject who performs the action of ordering the pizza, maintaining the simple past tense to reflect the action occurred at a specific past time.
Conversion rule:
Past indefinite
Subject + V2 + object. -> <- Object + auxiliary verb (was, were) + past participle + by + subject.