If x is the product of three consecutive positive integers, which of the following must be true
Ⅰ. x is an integer multiple of 3.
Ⅱ. x is an integer multiple of 4.
Ⅲ. x is an integer multiple of 6.
A．Ⅰonly
B．Ⅱonly
C．Ⅰand Ⅱonly
D．Ⅰand Ⅲonly
E．Ⅰ, Ⅱ, and Ⅲ