† and ¥ represent nonzero digits, and (†¥)^2 - (¥†)^2 is a perfect square. What is that perfect square?
Select the correct option:	A) 121	B) 361	C) 576	D) 961	E) 1089
Let the digits be a and b   (ab) can be written as (10a + b)   (ba) can be written as (10b + a)   (ab)^2 - (ba)^2 = (ab + ba)(ab - ba) = (10a + b + 10b + a)(10a + b - 10b - a) = 11(a + b)*9(a - b) = 99(a^2 - b^2)   99(a^2 - b^2) is a perfect square.   So the perfect square must be divisible by 99. Only option E is divisible by 99.   Answer: 1089
<result>E</result>
† and ¥ represent nonzero digits, and (†¥)^2 - (¥†)^2 is a perfect square. What is that perfect square?