Calculate how many seconds it will take for 4 bells to toll together again, given that they begin to toll together respectively at the intervals of 9, 10, 14 and 18 seconds. ?  Choose the correct choice from the following answers.
A) 636
B) 631
C) 633
D) 610
E) 630

Rationale: lcm of 9 , 10 , 14 and 18 is 630 lcm = 630 answer : e
Answer: E