Answer:
B, C
Step-by-step explanation:
The only statements that must be true are ones that describe the markings on the diagram:
NO as an angle bisector
N is the vertex of a pair of congruent angles
_____
The only other fact that must be true is that segments on the left side of the diagram are proportional to those (corresponding) on the right. (This is a property of the angle bisector.) There is nothing that says the sides must be equal, or that the triangle is isosceles.
The equivalence

means that n-5 is a multiple of 12.
that is
n-5=12k, for some integer k
and so
n=12k+5
for k=-1, n=-12+5=-7
for k= 0, n=0+5=5 (the first positive integer n, is for k=0)
we solve 5000=12k+5 to find the last k
12k=5000-5=4995
k=4995/12=416.25
so check k = 415, 416, 417 to be sure we have the right k:
n=12k+5=12*415+5=4985
n=12k+5=12*416+5=4997
n=12k+5=12*417+5=5009
The last k which produces n<5000 is 416
For all k∈{0, 1, 2, 3, ....416}, n is a positive integer from 1 to 5000,
thus there are 417 integers n satisfying the congruence.
Answer: 417