Let's denote the income of Kamran as "3x" and the income of Dolon as "4x" (based on the given ratio).

We're also given that Kamran's savings are one-fourth of his income, so Kamran's savings would be (1/4) * 3x, which simplifies to (3/4) * x.

Now, let's consider their expenditures. The ratio of their expenditures is 4:5. Let the common multiplier for both expenditures be "k."

So, Kamran's expenditure is 4k, and Dolon's expenditure is 5k.

Now, let's calculate their savings. Savings are calculated as Income - Expenditure.

Kamran's savings = Income - Expenditure = 3x - 4k Dolon's savings = Income - Expenditure = 4x - 5k

Now, we're given that Kamran's savings are (3/4) * x, so we can set up an equation:

3x - 4k = (3/4) * x

Now, let's solve for k:

3x - (3/4) * x = 4k

(12/4)x - (3/4) * x = 4k

(9/4) * x = 4k

Now, solve for k:

k = (9/4) * x / 4

k = (9/16) * x

Now, we have expressions for Kamran's and Dolon's savings:

Kamran's savings = 3x - 4k = 3x - 4(9/16) * x Dolon's savings = 4x - 5k = 4x - 5(9/16) * x

Now, simplify these expressions:

Kamran's savings = (48/16)x - (36/16)x = (12/16)x = (3/4)x Dolon's savings = (64/16)x - (45/16)x = (19/16)x

Now, we have their savings in terms of x:

Kamran's savings = (3/4)x Dolon's savings = (19/16)x

Now, let's find the ratio of their savings:

(Kamran's savings)/(Dolon's savings) = [(3/4)x] / [(19/16)x]

Now, simplify the ratio:

(Kamran's savings)/(Dolon's savings) = (3/4) / (19/16)

To simplify further, multiply both the numerator and denominator by 16:

(Kamran's savings)/(Dolon's savings) = (3/4) * (16/19)

Now, calculate the ratio:

(Kamran's savings)/(Dolon's savings) = (48/76)

Simplify the ratio:

(Kamran's savings)/(Dolon's savings) = 12/19

So, the ratio of their savings is 12:19. The correct answer is 12:19.