We can see the ratio of a side big figure and small figure is 60:15 or 60/15 = 1/4.
In decimal form we can write 1/4 as 0.25.
Therefore, scale factor is 0.25.
So, second option is applicable. Please check second option :
The scale factor is 0.25.
Now, let us find the side A by multiplying by scale factor 0.25 of the big figure.
The corresponding side of A is 35.
Therefore, A is 0.25 × 35 = 8.75 cm.
Therefore, other applicable option is 3rd option.
The length of side A is 8.75 cm.