Which of the following are independent pairs of events? check all that apply.
a. flipping two coins and having one show a head and the other show a head
b. being sneezed on and catching a cold
c. when rolling a pair of dice, getting a total of 6 and having one die show a 3
d. rolling a 4 on one die and rolling a 2 on another die
e. seeing clouds and winning the lottery