What does option listing agreement require?

What does an option listing agreement require?  An option listing agreement is where the broker purchase the property from the seller, and then resells the property and makes a profit from the resale.

  1.  Informing the principal of the resale of the property.
  2.  The broker must share the profit with the seller.
  3.  The broker must inform the principal of the resale of the property, any profits to be realized from the resale, and also obtain permission from the seller to proceed with the resale.
  4.  Nothing except a listing agreement.

The answer is C – Just informing the principal is not enough, they must also give you permission to proceed with a resale.