Subject :IMO Class : Class 10
Which of the following statements is incorrect?
A For natural numbers a and b, if a divides b2 then a divides b.
B For any natural number 
is irrational.
C Product of distinct prime numbers is always equal to their L.C.M.
D For any natural number n, 6n never ends with digit zero.
the answer is given wrong . The correct answer should be B