Given a sentence with a missing word, pick the answer option that best fills out the missing word in the sentence. Indicate each answer with its index ('a', 'b', 'c', 'd').
--------
Question: Heme is made of ____ pyrrole groups united to form a porphyrin ring.\Question: Choose the right answer from options given a) five b) four c) eight d) six

Answer: b


Question: Reverse osmosis uses ____ to ten gallons of water to produce one gallon of drinking water.\Question: Choose the right answer from options given a) two b) zero c) five d) three

Answer: d


Question: Child care is provided for children ages six weeks through ____ years of age.\Question: Choose the right answer from options given a) seven b) four c) two d) three

Answer:
b