Correct option is (c) Rs 150
Let the amount he saves every year be Rs. x
And the number of years saved till now = y
Given, now he has Rs 1200
⇒ xy = Rs 1200
As per the statement, "In four years time he will have three times as much as he had four years ago"
⇒ x(y + 4) = 3 × (x(y − 4))
⇒ xy + 4x = 3xy − 12x
16x = 2xy
16x = 2(1200)
x = 150
Hence, he saves Rs 150 every year.