Six playing cards are lying face down on a table, two of them are kings. Two cards are drawn at random. Let 'a' denote the probability that at least one of the cards drawn is a king, and 'b' denote the probability of not drawing a king. The ratio a/b is
(A)≥ 0.25 and < 0.5
(B) ≥ 0.5 and < 0.75
(C) ≥ 0.75 and < 1.0
(D) ≥ 1.0 and < 1.25
(E) ≥ 1.25


Now I have done this:

For 'a':
probability that at least one of the cards drawn is a king = (2/6)(4/5) + (2/6)(1/5)
(2/6)(4/5) is for one king drawn and another card drawn
(2/6)(1/5) is for the case where both the cards drawn are kings

For 'b':
probability of not drawing a king = (4/6)(3/5)

So
a
- =
b

(2/6)(4/5) + (2/6)(1/5)
----------------------
(4/6)(3/5)

8 + 2
------
12

=>10/12 = 5/6.

Is my answer correct??

But the official answer is E