Which of the following statements about broker commission is true?

Question $5$Select one:

a$.$

Commissions must be the same for all trades and all brokers in a stock exchange.

b$.$

If an option position is closed out by entering into an offsetting trade, the commission must not be paid again.

c$.$

Brokerage commissions in Australian Stock Exchange are normally charged as a portion of premium traded with a specified maximum.

d$.$

None of the above answers is true