The correct option is (b) leaf abscission.
Explanation:
Abscission is natural shedding of leaves, foliage branches, fruits, floral parts, etc. According to Leopold (1967) abscission is a senescence. phenomenon. Senescence is known as 'the sum of deteriorative processes which naturally terminate the functional life of an organism.
Senescence is not confined only to whole plant, it may be limited ta a particular plant organ such as leaf and flower or cells such as phloem and xylem, Senescence as an active developmental cellular process in the growth and functioning of a flowering plant, is indicated in leaf abscission.
Whole plant senescence also known as all senescence occurs in annuals, (e g., rice, wheat, gram, mustard), biennials (e. g. henbane) or perennials.
