For an acute triangle , each angle will be less than 90
And the sum of the angles will be 180
So, we will check the options :
A. 20 , 50 , 30
The sum of the angles = 20 + 50 + 30 = 100 < 180
the angles Could not be angles of the triangle
B. 20 , 90 , 70
one of the angles = 90
So, it is a right triangle ,
The angles Could not be angles of the triangle
C. 30 , 85 , 65
All of the angles less 90
The sum of the angles = 30 + 85 + 65 = 180
The angles Could be angles of the triangle
D. 120 , 45 , 15
One of the angles is greater than 90
It will be obtuse triangle
The angles Could not be angles of the triangle
So, the answer is : the angles ( 30 , 85 , 65 )