A particle, originally at rest and located at point (3 ft, 6 ft, 4 ft), is subjected to an acceleration of a = 6ti, 13t²k ft/s². What is the velocity of the particle after 2 seconds?
a) 12i + 52k ft/s
b) 12i + 26k ft/s
c) 24i + 104k ft/s
d) 24i + 52k ft/s