单项选择题

In a diesel engine, an integral liner is one in which the cooling water ()
Ⅰ.flows through the cylinder liner jackets
Ⅱ.touches the outer side of the liner

A.Ⅰ only
B.Ⅱ only
C.both Ⅰ and Ⅱ
D.neither Ⅰ and Ⅱ