The contract between a party who agrees to accept the risk and a party seeking protection from the risk a contract of_______

A．payment

B．production

C．shipment

D．insurance

夏天快到了，小伟在盛有凉开水的杯子中放入冰块做冷饮。当冰块熔化后（水未溢出），以下判断正确的是[ ]

A.杯中水面的高度升高

B.杯子对桌面的压力增大

C.水对杯底的压强减小

D.水对杯底的压力不变