An investor gathered the following information about two 7 percent annual-pay, option-free bonds: Bond R has 4 years to maturity and is priced to yield 6 percent Bond S has 7 years to maturity and is priced to yield 6 percent Both bonds have a par value of $1000. Given a 50 basis point parallel upward shift in interest rates, what is the value of the two-bond portfolio（）

A. $2044.

B. $2030.

C. $2086.

废品损失应该包括（）。

A.不可修复废品的报废损失

B.可修复废品的修复费用

C.不合格品的降价损失

D.产品保管不善的损坏变质损失