Select the option that expresses the given sentence in active voice.

Admittance was refused to him by the airport security.

The airport security refused him admittance.

The correct option that expresses the given sentence in active voice is The airport security refused him admittance.

The other options are incorrect because:

• Admittance was refused to him by the airport security is in the passive voice.
• The airport security is refusing him admittance is in the present progressive tense, while the original sentence is in the past tense.
• The airport security has refused him admittance is in the present perfect tense, which is not typically used for actions that happen once.
• The airport security had refused him admittance is in the past perfect tense, which is not typically used for actions that happen before another event.