In which type of planting are seedlings planted close to each other i.e. the spacing is kept lower than the normal spacing?

Correct option is A

High density planting involves planting crops with closer spacing than usual to increase the number of plants per unit area. This method is used to maximize land use and improve yields.
Examine each option:
(a) High density planting:
· Correct answer; it involves closer planting for increased yield per area.
(b) Quincunx system:
· A planting arrangement where plants are placed in a staggered pattern, not necessarily high density.
(c) Hexagonal system:
· Plants are arranged in a hexagonal pattern, which can be used for high density but is not specifically defined as such.
(d) Square system:
· Plants are spaced in a square grid pattern, which does not imply high density.
(e) Triangular system:
· Plants are arranged in a triangular pattern, not specifically high density.