Three bicycles are fitted with wheels that can make 6, 5 and 10 revolutions per minute respectively. One spoke on each wheel is painted blue. All three bicycles start moving at the same time, and the poke of the wheels painted blue is in the same position for all 3 bicycles. After how much time, will all the three wheels be a1igned in the same manner as they were at the starting? ( in seconds)

A

60

B

30

C

12

D

120