After rearranging answer choice we get ad in one quantity and bc in another quantity, But we are clear said that ad > bc , Thus quantity B must be greater. Carcass sir!

But you do not know the signs ....Sir

Hi there!

Lets try to solve it this way!

Give: ad>bc
bd<0 this means that either b or d should be negative

So if d is negative, and b is positive. a has to be negative (because ad>bc) and c has to be negative......(1)
If d is positive, and b is negative. a has to be positive and c has to be positive......(2)

Using 1
Qty A: b/a= negative/positive
Qty B: d/c=positive/negative


Using 2
Qty A: b/a= positive/negative
Qty B: d/c= negative/positive

Now as we don't have the value of a, b, c & d we do not know which is greater and which is lesser.

Thus D

Hope this helps!

a b c d
+-++
-+--
-++-

Either b or d should be - but not both. Test for these cases with a table and you should get D in 2 mins