-  Let Mr. Sohanlal’s age (in years) = X and his son’s age =Y
Then, X – 5 = 3(Y – 5) i.e. X – 3Y + 10 = 0
And, X + 10 = 2 (Y + 10) i.e. X – 2Y – 10 = 0
Solving the two equations, we get
X = 50, Y = 20.

Let Mr. Sohanlal's present age be x years and his son's present age be y years.
Then, according to the given information, five years ago,

x - 5 = 3(y - 5)
=> x - 5 = 3y - 15
=> x = 3y - 10

Also, ten years hence,

x + 10 = 2(y + 10)
=> x + 10 = 2y + 20
=> x = 2y + 10

Substituting the value of x from equation (1) in equation (2),

3y - 10 = 2y + 10
=> y = 20

Hence, Mr. Sohanlal's present age = 3 × 20 = 50 years

Therefore, the correct answer is Option D. 50 years.