Explanation:

Let the present ages be a,b,c
a+b+c = 93
Their ages 10 years ago are a-10,b-10,c-10
ratio of ages is 2:3:4
sum of ages 10 years ago is a-10+b-10+c-10 = a+b+c - 30 = 93-30 = 63
Let 2x,3x,4x be the ages
2x+3x+4x = 63x = 7
C's age 10 years ago = 4(7) = 28 years
C's present age = 28+10 = 38 years

Hence, option 4 is the correct answer.