For a particle undergoing SHM, the displacement x is related to time t as x = A cos ωt. In the graphs given below, its potential energy (PE) is plotted against t (1st graph) and x (2nd graph). Two options are shown in each graph, marked as 1 and 2 in the 1st and as 3 and 4 in the 2nd. Which of these are correct?
(a) 1 and 3
(b) 2 and 4
(c) 2 and 3
(d) 1 and 4