(b) There is no need to emasculate unisexual flowers of the selected female parent - This statement is correct because unisexual flowers do not have male reproductive parts (stamens), so there is no need to remove anthers (emasculate) to prevent self-pollination.

(c) Emasculated flowers are to be bagged immediately after cross-pollination - This statement is correct because, after cross-pollination with the desired pollen, the flowers need to be bagged to prevent further contamination from unwanted pollen or other pollinating agents.

(d) Emasculated flowers are to be bagged after removal of anthers - This statement is correct. The emasculated flowers should be bagged after anther removal and before cross-pollination. This prevents contamination with unwanted pollen. After cross-pollination, the flowers should be bagged again to avoid any further contamination.

The other options are incorrect :

(a) The female flower buds of plant producing unisexual flowers need not be bagged - This statement is incorrect because even unisexual flowers need to be bagged to prevent contamination from unwanted pollen or other pollinating agents.

(e) Bisexual flowers, showing protogyny, are never selected for cross - This statement is incorrect because protogyny (when the female reproductive part matures before the male reproductive part) can reduce the chances of self-pollination, making these flowers suitable for cross-pollination.