The correct option is D √4160 m/s2
Let the tangential acceleration be at
and centripetal acceleration be ac
Its speed is given by v=2t2
at=dvdt=4t
∴ at t=2 s,
at=4(2)=8 m/s2
Now for the centripetal acceleration,
ac=v2R
At t=2 s,v=2×22=8 m/s
⇒ac=821=64 m/s2
∴anet=√a2c+a2t=√642+82=√4160 m/s2
Hence option D is the correct answer.