The correct option is B Semi-presidential system.
Sri Lanka is a democratic republic with an executive presidency which means that dual executive or semi presidential system exists in Sri Lanka in which a President exists along side the Prime Minister and Cabinet. Under Presidential system President is the chief executive head elected directly by the people e.g. US. Parliamentary system is one where executive is directly responsible to the legislature e.g. U.K. The Monarchial system is one where the sovereignty and power resides in one person called Monarch and who is the sole decision making authority. e.g. Cambodi, Gulf nations.