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").

Fact1: tidal energy can be used to produce electricity, Fact2: Tidal caves are formed by the energy of the rising and falling tides., Question: what can produce electricity? (A) rivers (B) animal transport (C) tidal caves (D) Nematoda (E) rays or beams (F) animals (G) cactuses (H) photons
C

Fact1: pollutants have a negative impact on the environment, Fact2: Carbon dioxide is a pollutant., Question: What affects the environment negatively? (A) sunlight (B) normal weather patterns (C) carbon dioxide (D) cigarettes (E) positivity (F) Smoking (G) harmful substances (H) fossil fuels
C

Fact1: Biodiversity increases the productivity and stability of ecosystems., Fact2: Biodiversity is basically genetic diversity., Question: What increases the productivity and stability of ecosystems? (A) Fully cooking the oysters (B) genetic uniformity (C) genetic diversity (D) extinction (E) agriculture (F) disease (G) Earth orbiting the Sun (H) recycling
C