THE ANSWER WOULD BE:
C. ALL EQUILATERALTRIANGLES ARE ALSO ACUTE TRIANGLES.
BECAUSE:
a. cannot be true if the angles are 59, 60, 61.
b. this can also be a right (non-isosceles) triangle
l \
l \
l__\
d. if the triangle is obtuse, one angle has to be greater than 90 degrees and if you add a right angle (which is 90 degrees) it would be over the triangle's number of degrees (180)