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").
Example: Fact1: a plant requires sunlight to grow, Fact2: Plants to avoid are fast-growing vines that can take over an area in no time., Question: What requires sunlight in order to take over an area? (A) spores (B) fish (C) plants (D) humans (E) pods (F) Oak (G) opossums (H) coral
Example solution: C
Example explanation: This is a good example. Based on the facts plants require sunlight in order to take over an area.

Problem: Fact1: Sponges have specialized cells called collar cells., Fact2: Special cells called collar cells pick up the planktonic food and start the digestive process., Question: What do sponges use to collect and digest food? (A) bloated stomachs (B) non-bacterial prokaryotes (C) specialized cells (D) holding nutrients (E) dermal & vascular tissue (F) specialized limbs (G) large mouth (H) unicellular organisms
Solution: C