সহায়িকা

Explanation
Comes off is the correct phrasal verb to replace "will be held" in the given sentence. In this context, "come off" means to happen, take place, or be successful. It is often used for scheduled events, even if they are in the future, as the present tense can be used for fixed future events, or the phrasal verb itself implies the future action.

Why other options are incorrect
A. takes off means to leave the ground (like an airplane), to remove something, or to suddenly become successful. It does not mean to "be held" or take place.
C. will bring about means to cause something to happen or produce a result. It is an active verb phrase about causing an event, not the event itself being held.
D. will come round means to recover consciousness, to visit someone's house, or to change one's opinion. It is not a synonym for an event being held.

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