They would have multiple problems and or moods
<h3>
Answer: B. Studied</h3>
We're talking about event in the past (last night), so we use a past tense form of the verb "to study".
Danny <u>studied</u> for a long time last night.
The subject does agree with the verb because the subject is students and the verb is use. The subject is plural and the verb is singular.
What are the options? As soon as you put them on the question I'll be glad to answer your question :)