Answer:
C. 17
Explanation:
The mean weight can be calculated by adding the numbers 15 + 16 + 15 + 13 + 19 + 20 + 21 divided by the number 7, which is the amount of numbers you just added.
(15 + 16 + 15 + 13 + 19 + 20 + 21)/7
the outcome = 17 which corresponds to answer C.