Assertion: In flowering plants, the pollen tube enters the ovule through the chalazal end.
Reason: The micropyle is a small opening in the integuments of the ovule that allows the entry of the pollen tube.
Both assertion and reason are true, and the reason is the correct explanation of the assertion.
Both assertion and reason are true, but the reason is not the correct explanation of the assertion.
The assertion is true, but the reason is false.
The assertion is false, but the reason is true.
The correct statement is that in flowering plants, the pollen tube enters the ovule through the micropyle, not the chalazal end. The chalaza is the region of the ovule where the integuments and the nucellus join, and the micropyle is a small opening in the integuments of the ovule that allows the entry of the pollen tube.
So, the reason is true since the micropyle is indeed the opening that allows the pollen tube to enter the ovule. However, the assertion is false because the pollen tube does not enter through the chalazal end but through the micropyle. Therefore, option (d) is the correct answer.