The correct option is B is going to break down / don't take it
The given sentence is a first conditional sentence. It talks about real possibilities in the present or the future. The first blank will take the present continuous tense as it is used for a temporary action which may or may not be taking place at the time of speaking.
So, option C is correct as 'is going to' indicates the present continuous tense. The second blank takes the 'if' conditional and gives the negative 'don't take it' in simple present tense.
Option A is incorrect as the tenses do not concur for both the blanks.
Option B is incorrect as the option for the blank for the if conditional is incorrect.
Option D is incorrect as 'won't take it' is in future tense whereas, the first conditional 'if' clause is in simple present tense.
Thus, option C is correct.