Which of the following is an example of qualitative data?

a. The fish swam in a zigzag motion.
b. The contents of the stomach are mixed every 20 seconds.
c. The temperature decreased from 20 degrees C to 15 degrees C.
d. The six pairs of robins hatched an average of three chicks.

Now I'm pretty sure it's a but I was thinking c as well, pls help