Which two statements relating investment costs and returns are correct?

a. Returns typically increase when investors pay a back-end load for every fund sold.

b. Returns may be lower than expected when investors pay brokerage fees for trading.

c. Returns may be higher when investors are charged inactivity fees.

d. Returns may be lower than expected because investors pay taxes on all income earned.

e. Returns may be higher than expected when investors pay commission to brokers.