One end of a string of length l is connected to a particle of mass m and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed v the net force on the particle (directed towards the centre) is
(a) T
(b) T−

mv2

l

(c) T+

mv2

l

(d) 0
T is the tension in the string. [Choose the correct alternative].