The subject is “milk.” The prepositional phrase is “in the cup.” The verb is “is.”
That's not a full sentence. "the glacier" is a phrase, not a sentence.
Answer: A friend is a person with whom I may be sincere.
Explanation:
The speaker says that a friend is someone they can be sincere with. This means that to the speaker, the underlying advantage of friendship is sincerity. Friends can be honest and truthful with one another more than others and so it can be said that honesty holds a friendship together.
This is why honesty is important in a friendship. If friends cannot be honest with one another, the friendship is fractured and according to the speaker, cannot even be referred to as friendship.
