Answer:
In 1897, attending Harvard as a non-degree student is a fragment.
Step-by-step explanation:
Group of words which apparently look like sentences but actually are not are called fragments or sentence fragments.
These fragments need at least one independent clause to become a complete sentence. An independent clause is a group of words which consists of both a subject and a verb and can stand on its own.
'In 1897, attending Harvard as a non-degree student' is a fragment since it does not have any independent clause and does not make any sense on its own.