Which among the following statements are correct :

(A) Continued cross -pollination result in inbreeding depression.

(B) In case of castor and maize , it prevent autogamy but not geitonogamy.

(C) In papaya, it prevents  geitonogamy but not autogamy .

(D)  The pistils has the ability to recognise the pollen, whether it is of the right type (compatible) or of the wrong type (incompatible).

B and D only 

The correct answer is Option (2)- B and D only
Continued self-pollination result in inbreeding depression.

If both male and female flowers are present on the same plant such as castor and maize (monoecious), it prevents autogamy but not geitonogamy.

In several species such as papaya, male and female flowers are present on different plants, that is each plant is either male or female (dioecy). This condition prevents both autogamy and geitonogamy.

Pollen of the wrong type, either from other species or from the same plant (if it is self-incompatible), also land on the stigma. The pistil has the ability to recognise the pollen, whether it is of the right type (compatible) or of the wrong type (incompatible). If it is of the right type, the pistil accepts the pollen and promotes post-pollination events.