What is the branch of linguistics that studies meaning?

Which of these sentences would best express the main idea of a speech arguing that people should participate in a charity softball tournament? a) softball is a great way to get some much-needed exercise. eliminate b) the money raised by the tournament will local animal shelters. c) the tournament is a fun way to spend time with friends while a worthy cause. d) even if you don't have any softball experience, you can form a team and participate.