Explanation:
the area of a full circle (360°) is
pi×r² = pi×5² = pi×25
a 40° segment is then just 40/360 = 1/9 of the full circle.
so,
pi×r²×1/9 = pi×25/9 = pi×2.777777777...
so, either there is a mistake in the problem description, or your teacher wants you to cut off the decimals (after the decimal point), in which case D would be the right answer.
since our radius is 5, that makes r² always 25.
there are no integer factors I can divide 25 by to create any of the 4 solutions of 16 or I or 4 or 2.
and there is no integer factor I can divide 360 by to get 25.
so, something is wrong here regarding the problem description. either the radius or the angle or the solution options are wrong and not fitting to each other.