“Deleterious” means something that causes harm or damage.
Option C Is the correct answer because “noxious “ means something that’s harmful, poisonous or dangerous, hence it is the correct meaning of the given word.
Option A is incorrect because “effective” means successful in producing a desirable result, hence it is not the correct meaning of the given word.
Option B is incorrect because “intoxicating” means liable to cause someone to lose control of their faculties or behaviour, which is not the correct meaning of the given word.
Option D is incorrect because successful means to achieve success which is incorrect.