Entry of pollen tube into the synergids is guided by:

The correct answer is Option (4) → Filiform apparatus

The egg apparatus of the embryo sac has two synergids and one egg cell. It lies at the micropylar end of the ovule.

(1) Stigma — Incorrect. The stigma receives the pollen grains and the pollen germinates on it. It is the landing platform for the pollen.

(2) Style — Incorrect. The pollen tube grows through the style to reach the ovary. The style does not guide it into the synergids.

(3) Micropyle — Incorrect. This is the small opening of the ovule through which the pollen tube enters the ovule. The tube enters the synergid later, after passing it.

(4) Filiform apparatus — Correct. The synergids have special thickenings at the micropylar tip, called the filiform apparatus. It plays an important role in guiding the pollen tube into the synergid.

NCERT Extract:
The Pistil, Megasporangium (ovule) and Embryo Sac – …