Which of the Following Is a True Statement

Which of the following is a true statement?

A) It is easy to predict the probability and length of a foreign country's recession.
B) Although economists understand the relationship between risk and return, they have been unable to develop a way to quantify it.
C) There is a direct relationship between risk and expected return.
D) Risk and the likelihood of realizing future cash flows from an investment are unrelated.
E) Riskless investments do not usually earn a positive return.