Pollen grains are shed at 2 celled stage in:

The correct answer is Option (3) → More than 60% of the angiosperms

A young pollen grain has a vegetative cell and a generative cell. This is the 2-celled stage. In some plants the pollen grains are shed at this stage. In the rest, the generative cell divides before shedding to give two male gametes, so the grain is 3-celled when it is shed. In more than 60 per cent of angiosperms, the pollen grains are shed at the 2-celled stage.

NCERT Extract:
Stamen, Microsporangium and Pollen Grain – “… When the pollen grain is mature it contains two cells, the vegetative cell and generative cell (Figure 1.5b). The vegetative cell is bigger, has abundant food reserve and a large irregularly shaped nucleus. The generative cell is small and floats in the cytoplasm of the vegetative cell. It is spindle shaped with dense cytoplasm and a nucleus. In over 60 per cent of angiosperms, pollen grains are shed at this 2-celled stage.”