Match List-I (Kinds of aperture) with List-II (Characteristic features) and select the correct answer:

List-I	List-II
a. Sulcus	1. A round aperture if present in small numbers pori are found in the equatorial region
b. Colpa	2. A longitudinal furrow is found to the distal half of the pollen grain, crossing the pollar axis at right angles
c. Ruga	3. A meridional furrow crossing the equator at right angles and directed at each end to the polls of the pollen grain
d. Porus	4. A furrow is found irregularly on the grain surface