Possible answers, 35, 30, 90,64

Answer:
30
Step-by-step explanation:
this is a right-angled triangle.
as we can see on the graph and the coordinate units,
AB = 4
BC = 7
=>
AC² = AB² + BC² = 4² + 7² = 16+49 = 65
AC = sqrt(65)
now, in every triangle there are certain ratios equal to each other.
a/sin(A) = b/sin(B) = c/sin(C)
a is here BC
b is here AC
c is here AB
and we know B = 90 degrees
sin(90) = 1
so, we have
sqrt(65)/1 = 4/sin(C)
sqrt(65) = 4/sin(C)
sin(C) = 4/sqrt(65) = 0.496138938...
C = 29.7448813...
the closest answer option is 30.