A coil of area of crosssection 0.5 m2 is placed in a magnetic field acting normally to its plane. The field varies as B=0.5t2+2t , where B is in tesla and t is in seconds. The emf induced in the coil at t=1 s is
(a) 0.5 V
(b) 1.0 V
(c) 1.5 V
(d) 3.0 V