(A)    Alteration in the gene content of leaves of reproductive phase from those of vegetative phase.
(B)    Differential methylation pattern of genes influencing leaf development and morphology.
(C)    Mutation in transcription factor that prevents its association with promoter elements of genes regulating leaf development.
 (D)    Small RNA mediated inhibition of gene expression of a homeotic gene.
 Which one of the following options represents a correct combination of statements that could explain the observed changes ?