In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").

Ex Input:
Fact1: planting trees has a positive impact on an ecosystem, Fact2: An ecosystem contains many habitats., Question: doing what with trees has a positive impact on habitats (A) making tables (B) chopping down (C) planting (D) watershed (E) earth (F) bloom time (G) growth (H) timbering

Ex Output:
C

Ex Input:
Fact1: a compass is used to navigate oceans, Fact2: And to the east is the Atlantic Ocean., Question: what is a compass used to navigate? (A) density (B) lamphreys (C) marine (D) outer space (E) their speed (F) Antarctica (G) non-magnetic planets (H) the Atlantic

Ex Output:
H

Ex Input:
Fact1: Echinoderms lack a centralized nervous system., Fact2: Echinoderms include starfish, sea urchins, and sea cucumbers., Question: Starfish, sea urchins and sea cucumbers lack a what? (A) characteristics (B) the body's largest organ (C) watery habitat (D) centralized nervous system (E) functioning arm (F) underwater life (G) biological diversity (H) epidermis and dermis

Ex Output:
D