Fill in the blank with appropriate word.
________many times do you smoke? [Basic]
Correct option is C. How
Here option C is the correct answer.
In this question, the speaker is asking about quantity. He/She wishes to know the number of cigarettes smoked by the listener. Therefore, we use the word 'How'.
Uses of Wh-Questions:
What: to ask for information about things and actions.
Eg: What is your name?
When: to refer to a situation or condition that we are certain of in future times. Eg: When is Rita coming?
How: is an adverb that means in what way or to what extent. It is used to introduce questions about measurements (Length, breadth, height) or amounts.
Eg; How many times do you smoke?
Who: should be used to refer to the subject of a sentence.
Eg; Who are you?
Hence options A, B, and D are incorrect.