Which of the following groups contain only biodegradable items?

(a) Grass, flowers and leather

(b) Grass, wood and plastic

(c) Fruit peels, cake and lime juice

(d) Cake, wood and grass

(a) (c) and (d) groups contain only biodegradable items. Plastic in option (b) is non-biodegradable so option (b) does not contain biodegradable items. The groups (a (c) (d) have grass, flowers, leather, fruit peels, cake, lime juice, wood which are biodegradable.