Question

"National Yo-Yo Day is observed with tournaments around the country."

Answer 1

The underlined verb is 'is observed.' The form of that verb is B. passive.
Active form would be 'People observe the National Yo-Yo Day...'

Answer 2

The underlined verb is 'is observed.' The form of that verb is B. passive.
Active form would be 'People observe the National Yo-Yo Day...' Imperative form is giving commands, so it would be something like - Please go and observe that! Subjunctive form would be - If I were you,I would observe...