E. Barnes, Professional Gamer, Professional Gamer, Washington
Answered Feb 26, 2019
Juan is studying in the library this morning. A gerund is needed in this sentencem which would be "studying," but the correct verb would be "is" in this case because the subject is singular, so the verb would also need to be singular.
If the subject were a group of people or more than one person, then you would choose "are studying." For example, Juan and Emily are studying in the library this morning. There is a gerund and the verb is plural because the subject of the sentence is more than one person.
The others do not make enough sense to be suitable answers for this. In the above sentence 'is studying' a present participle and not a gerund. Pointing that out for better understanding.