Option 1 -> Excludes Complementary Goods (C) which influences demand elasticity through cross-price effects.
Option 2 -> Incorrectly includes Cost of Goods (D) which is not a standard factor of price elasticity.
Option 3 -> Correctly identifies Nature of Goods, Availability of Substitution, and Complementary Goods as key factors.
Option 4 -> Excludes Nature of Goods (A) and incorrectly includes Cost of Goods (D).
Hence, Option 3: (A), (B), and (C) -> The main factors affecting price elasticity of demand are: (A) Nature of Goods - necessities are inelastic while luxuries are elastic; (B) Availability of Substitution - more substitutes make demand more elastic as consumers can easily switch; (C) Complementary Goods - the availability and price of complementary goods affect the demand elasticity of the main product. Cost of goods is not a determinant of price elasticity, rather it's the other factors like income proportion, time period, and consumer preferences that matter. -> correct