我国常用的几种价格，从保险角度来说可分为（）。

A.不带保险的CIF

B.带保险的FOB和CFR

C.带保险的CIF

D.不带保险的FOB和CFR

E.带保险的FOB和CIF

For an unconditional probability（）

A. there are at least two events.

B. the joint probability rule is important.

C. there is only one random variable of concern.