Answer: (D) Using direct response advertising
Step-by-step explanation:
The direct response advertising is one of the type of promotional method where the customers are requested for the direct and quick respond to the marketer.
We using this direct response advertising method s that we can easily or fastly interact with the customers for the immediate response or the feedback.
According to the given situation, the direct response advertising strategy is one of the best method for increasing the syringes sales in the market that basically filter water. Therefore, Option (D) is correct.