How are plants propagated using
leaf and leaf-bud cuttings?

Remove a leaf and include up to 11⁄2 inches of the petiole. Insert the lower end of the petiole into the medium (Figure 1). One or more new plants will form at the base of the petiole. The new plants are then severed from the original leaf-petiole cutting and the cutting may be used once again to produce more plants.

Letter a, because when there are unlike charges they will always attract to each other.