The correct option is
D Cling to
“Hold by” means to stick to a decision or a thought or an opinion.
“Delay” means to make it late, to extend the time.
”put forward” means to bring into account, to bring attention to.
“Offer” means a proposal that is subject to acceptance or rejection.
“Cling to” means stick to, or abide by.
“Keep back” means to put back in place.
Hence option D is the correct answer because it is the correct meaning of the given phrase.