Answer:
A. 19.8 cm.
Explanation:
The apparent depth of the combination is
As it mentioned that the two clear but non-mixing liquid having depth of 15 cm that placed in a glass container together
Also the refractive indices would be 1.75 and 1.33
Based on the above information
As we know that
Refractive indices = real depth ÷ apparent depth
1.33 ÷ 1.75 = 15 ÷ apparent depth
So, it would be 19.736842 cm
Now the combination of apparent depth would be
= ( 19.736842 + 15) ÷ (1.75)
= 19.8 cm
hence, the correct option is A.