Let the coupon payments of A, E, B, D and C be a-2d, a-d, a, a+d, and a+2d, respectively.
Since, the coupon payment of A is twice the common difference,
a - 2d = 2d
a = 4d
Thus, the coupon payments of A, E, B, D and C are 2d, 3d, 4d, 5d, and 6d, respectively.
Since the coupon payment on bond B is half the price of bond A, the price of bond A = 2 x 4d = 8d.
Let the price of bond E be $$x$$. Thus, the price of bond B = $$1.75x$$.
Let the face value of bond E be $$e$$. Thus, the face value of bond B = $$2e$$.
Since the face value of bond C is equal to the price of bond A, the face value of C is 8d.
We know that three of the bonds mature in two years, one in three years and one in five years. We are also given that A matures in 2 and D matures in 5 years.
Tabulating the given information.
Applying the price formula for A, we get
8d = $$\frac{2d}{1.25}+\frac{2d}{1.25^2}+\frac{1000}{1.25^2}$$
Solving this, we get $$d=125$$
Thus, the coupon payments of A, B, C, D, and E are 125, 500, 750, 625 and 375, respectively.
Price of A = 8d = 1000 = Face value of C
We are given that the price of bond C is more than 1800. The time period for C could be 2 or 3 years.
Case 1: Time period is 2 years.
Applying the price formula for C.
Price = $$\frac{750}{1.25}+\frac{750}{1.25^2}+\frac{1000}{1.25^2}$$
Price = 1720 (<1800)
Thus, the maturity period of bond C is 3 years and for bonds B and E will be 2 years.
Applying the price formula again, we get
Price = $$\frac{750}{1.25}+\frac{750}{1.25^2}+\frac{750}{1.25^3}+\frac{1000}{1.25^3}$$
Price of C = 1976
Using the price formula on bond B, we get
1.75$$x$$ = $$\frac{500}{1.25}+\frac{500}{1.25^2}+\frac{2e}{1.25^2}$$ ...(1)
Using the price formula on bond E, we get
$$x$$ = $$\frac{375}{1.25}+\frac{375}{1.25^2}+\frac{2}{1.25^2}$$ ...(2)
Solving equations (1) and (2) simultaneously, we get
$$x=1440$$ and $$e=1406.25$$
Thus, the table becomes
Since Madhubala has Rs. 2500, she can either buy one bond each of A and E, or a single bond C.
Return from bonds A and E = 1000 + 2(250) + 1406.25 + 2(375) = 3656.25
Return from bond C = 1000 + 3(750) = 3250
Thus, the maximum return that Madhubala can get is Rs. 3656.25.
Hence, the answer is option C.