Answer: a) the policy is highly visible.
Step-by-step explanation:
Politician tend to perform maximum activities and works according to voter's will when the political plan is perceived by the voters clearly.They follow the policy because they are discovered by the voters in well known manner.If they don't follow the policy they might not receive votes next time or voters will disregard the politician.
Other options are incorrect because information persisting voters,media intervention and absence of special interest group are not the factors that influence political to perform activities as per voters's desire.Thus, the correct option is option(a)