Sample space is $S :\{\text{Monday-Tuesday, Tuesday-Wednesday, Wednesday-Thursday}\ldots \text{Sunday-Monday}\}$
Number of elements in $S = n(S) = 7$
What we want is a set $A$ (say) that comprises of the elements $\text{Saturday-Sunday and Friday-Saturday}$
Number of elements in set $A = n(A) = 2$
By definition, probability of occurrence of $A =\dfrac{n(A)}{n(S)} = {2}/{7}$
Therefore, probability that a leap year has $53$ Saturdays is $\dfrac{2}{7}.$
Correct Answer: $A$