19. What is the result of the following MATLAB command: subs(sin(x), x, pi)? a) 1 b) 0 c) -1 d) sin(pi) 20. What is the function of the elseif statement in MATLAB? a) To define an alternative condition to an if statement b) To create a loop c) To execute a block of code regardless of the previous condition's result d) To end an if statement