Complete the sentence.
You really should see her. Why do you keep_______.
A. Putting it on
B. Putting it away
C. Putting it off
D. Putting it down

Hint: In the question we are going to find which word is applicable in this sentence. Sentence structure depends on where you are writing. If you create a sentence, it should have the proper meaning. In the given sentence, it means the person spoken to is delaying seeing her and the speaker is asking for reason. So put all the options and find which it makes a meaningful sentence.

Complete step by step answer:
Let’s discuss the given options and find the correct answer.

A. Putting it on: it means that to place or set somewhere including to cover a part of your body with a piece of cloth like,raman putting on her court and going out,a switch is touched with wet hands while putting it on. Hence option A is incorrect.
B. Putting it away: putting it away means store something in its usual place. Example of putting away like, she finished putting the water away and turned around. Hence the option B is incorrect .
C. Putting it off: putting it off means delaying something constantly and consistently. In the given sentence “you really should see her” it means that the person spoken to is delaying seeing her and the speaker is asking the reason for the same. So the correct option is putting it off. Hence, option C is correct.
D. Putting it down: putting it down means to bring to and end like, stop, put down a riot. Hence option D is incorrect.

Hence, The option C: putting off is the correct answer.

Note:
A preposition needs an object, rather like a transitive verb. A prepositional phrase is formed of an object, a preposition and words that enhance the value of the object.