Please explain

Q13. A particle of mass m is attached to a fixed point O by a weightless inextensible string of length a. It is rotating under the gravity as FO shown in the figure. The Lagrangian of the particle is L(0,)=ma0sin 00-mga cos where 0 and o are the polar m angles. The Hamiltonian of the particles is 8 1 (a) H P 2ma? P 1 Pt +mga cos6 2ma mga cos 6 (b) H= sin 0 sin (c) H= 2ma mga cos 6 (d) H = p+p)+ mga cos 0 2ma