收入乘数的驱动因素中的关键因素是（）。

A．销售净利率

B．股利支付率

C．增长率

D．权益成本

How are riveted lap joints made watertight（）.

A.The faying surfaces are coated with white lead（or similar product）before the rivets are set

B.A sealing weld bead of 1/8 or less pitch is run along the plate edge

C.The plate edge is split close to an adjacent plate and mechanically forced into contact with the adjacent plate

D.A properly riveted joint will be watertight; any leakage is stopped by setting up on the rivets