You can use it for research
Superlatives are verbs that show degree, examples are good, better, best OR bad, worst, worse.
Because there are three or more being compared you want BEST so that answer is most skillfully.
You need an objective pronoun here, and the only such pronoun is <em>us. </em>All of the other pronouns are subject pronouns.
The animated movie was more enjoyable to the children that to us. The correct answer is D.
