Answer:
A.
Step-by-step explanation:
If you draw a triangle reflecting the side length values given, you will get
(not drawn to scale), and the biggest angle in a triangle is opposite of
the longest side therefore since <A is opposite of 20 it is the largest and since B is opposite the second longest it is the second largest and since C is opposite of the shortest it is the smallest.
B
|\
20 | \ 16
| \
|__\ A
C 17