"Had held" is the past perfect tense of the verb "to hold." It is used to describe an action that happened before another action in the past. In this case, the action of "holding" happened before the action of "arriving."
"Hold" is the present tense of the verb "to hold." It is used to describe an action that is happening now. In this case, the action of "holding" would be happening at the same time as the action of "arriving."
Therefore, "had held" is the correct answer because it is the past perfect tense of the verb "to hold" and it is used to describe an action that happened before another action in the past.