Answer:
Option A. 0.25
Explanation:
Ellen plans two children but does not know if they will be boy-boy, girl-girl or boy-girl.
For the first baby to be the girl child
Probability =

Similarly probability for second baby to be the girl child will be

Now both the children are girl to probability for this event will be
=
×

=

= 0.25
Option A. 0.25 is the answer.