Researchers Report That People Who Smile Frequently Are More Likely

Multiple Choice

Researchers report that people who smile frequently are more likely than other people to have many friends. Which of the following conclusions can we draw, if any?

A) Smiling increases the probability of making friends.
B) We can draw none of these conclusions.
C) Some other factor, such as health, increases both the probability of smiling and the probability of making friends.
D) Having friends makes one happy and increases the probability of smiling.