It says that ,
She divides circumference by diameter
And we know the formulas for circumference and diameter
Circumference =

And Diameter =

And now lets divide circumference by diameter
Circumference/ diameter =
=

It simplifies to

So every time on dividing circumference by diameter , she will get

And value of
is 3.14 .
So everytime she will get 3.14
So option C is the correct answer.