Answer:
A. a partially disclosed principal.
Explanation:
In terms of a partially disclosed principal, the agent does not reveal about the identity of the principal. The agent reveals some information but not the complete one. In the above case, Gina discloses that she is buying the gift for some other person. This information is partially provided to Kelvin about the identity of the person. Hence, the principle here is partially disclosed to him.
The USS Maine exploded in Cuba’s Havana harbor. This ignited the war because the US believed that the Spaniards had something to do with it.
I think your answer would be according to some things you wrote on your question, income taxes.
The second sentence, "The science director's assistant placed the order yesterday afternoon," is written in active voice.