Let the bigger sphere be sphere 1 and the let the smaller sphere be sphere 2. Rest of the answer is in the picture.
Answer:
magnification will be -0.025
Explanation:
We have given the radius of curvature = 12 cm
And object distance = 3 m
So focal length 
Now for mirror we know that
So 

v = 0.750 m
Now magnification of the mirror is 
Well, your muscles are made of of the two (most important) filaments. When one of them moves over the other <span>filaments, the muscles is contracted. If there is an answer choice, I may be able to provide you with a more accurate answer, if this did not already help. ;)</span>