Mark Sims is exploring the characteristics of stock market investors. He found that sixty per cent of all investors have a net worth exceeding $1,000,000; 20% of all investors use an online brokerage; and 12% of all investors a have net worth exceeding $1,000,000 and use an online brokerage. An investor is selected randomly, and E is the event 'net worth exceeds $1,000,000', and O is the event 'uses an online brokerage'. Which of the following is true?

a. E and O are mutually exclusive

b. E and O are not independent

c. E and O are collectively exhaustive

d. E and O are independent

Mark Sims is exploring the characteristics of stock market investors. He found that sixty per cent of all investors have a net worth exceeding $1,000,000; 20% of all investors use an online brokerage; and 10% of all investors a have net worth exceeding $1,000,000 and use an online brokerage. An investor is selected randomly, and E is the event 'net worth exceeds $1,000,000', and O is the event 'uses an online brokerage'. Which of the following is true?

a. E and O are not independent

b. E and O are collectively exhaustive

c. E and O are mutually exclusive

d. E and O are independent