Which of the Following Is an Example of Indirect Transmission

Which of the following is an example of indirect transmission?

A) The backpacker refilled his water container from a faucet in the park labeled "potable water."
B) The biologist decided to set up his living quarters in one of the dusty caves,which he first swept out.
C) The nursing assistant first put on a pair of gloves and then picked up the soiled dressing.
D) The waiter went to the rest room,scrubbed his hands,and then returned to serving the meal.