Correct Answer - B
Consider the following events :
A=Number 4 appears at least once,
B=The sum of the numbers appearing is 6.
∴
Required probaility
=P(A/B)
= Probability of occurrence of A when B is taken as the sample space
Number of elementary events favourable to
=
A which are favourable to B
Number of elementary events favourable to B
=
2
5