Monopolists want to protect their market position by – potential competitors. a common tactic is to lobby for –, such as –. such lobbying is a form of –: use of political means to secure a – position.

restricting the entry; trade restrictions; import tariffs; rent-seeking; monopoly

Explanation:

Monopolists want to maximize their profits by keeping the potential competitors out of the market. For restricting the entry of potential firms they adopt the practice of lobbying for trade restrictions which restrict entry. One such restriction is importing tariff which will reduce competition from foreign products. Such lobbying can be defined as a form of rent-seeking which means using political means to secure monopoly position.

the answer is either c or b, i cant be to sure tho.