In an experiment, 30 squid are given vitamins and 30 squid are not given vitamins, in order to see if vitamins allow squid to make more
ink. It was found that the average amount of ink produced in the
control group (no vitalnins) was 20 ml per squid. The average in the
experimental group was 30 ml. Which of the following is a reasonable
conclusion?

A. Vitamins have no effect on squid ink production.

B. Squid should be given vitamins every day.

C. Vitamins seem to cause an increase in ink production.

D. Squid that use vitamins are healthier than squid that don't use
vitamins.