Product of two natural numbers is 19. Then, the sum of reciprocals of their squares is  Choose the correct choice from the following
A) 290/289	B) 1/289	C) 290/90	D) 362/361	E) None of these
Explanation:   If the numbers are a, b, then ab = 19,   as 17 is a prime number, so a = 1, b = 19.   1/a2+1/b2=1/1(2)+1/19(2)   1/ 2+1/ 2= 
<gadget id="calculator">1/ 2+1/ 2</gadget>
<output>1</output>
1/1(2)+1/19(2)=362/361   Option 362/361
<result>D</result>
Product of two natural numbers is 19. Then, the sum of reciprocals of their squares is