Investors make decisions to purchase the stocks and bonds of corporations based on:

A) ​Expected future cash flows
B) ​The issuing company's marketing strategy
C) ​Risk
D) ​All of the above
E) ​A and C only

Investors primarily make decisions based on the expected future cash flows and the level of risk associated with purchasing the stocks and bonds of corporations. The marketing strategy of the issuing company may have some impact on an investor's decision, but it is not one of the primary factors. Therefore, the correct answer is A and C only.