How are risk and return usually related?

A$.$ Balancing risk and return is of the most difficult tasks of investing. Risking too much might lose someone money, and risking too little may result in little to no return.

B$.$ The ratio of risk to return is equal to the ratio of annual return to total return.

C$.$ Risk and return are two out of the three general considerations made when evaluating what type of investment to make.

D$.$ Calculations of risk and return are used to make the index which reflects the average prices of the stocks of many large companies.