What angular velocity in revolution per second is needed for a centrifuge to produce an centripetal acceleration of a=9800m/s square at radius 10 cm.

Option (d) is correct.
Explanation:
centripetal acceleration = a = r ω²
r= radius= 10 cm= 0.1 m
ω= angular velocity
9800= (0.1) ω²
ω=313 rad/sec
ω= 313 rad/s * (1 rev/2π rad)
ω=49.8 rev/s