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').

Batteries consist of ____ electrodes immersed in an electrolyte.\Question: Choose the right answer from options given a) two b) eight c) three d) seven
a

Pistillate flowers have a compound ovary with ____ locules topped by three sticky, sessile stigmas.\Question: Choose the right answer from options given a) zero b) three c) six d) seven
b

Soy products contain ____ known classes of anti-cancer agents, including phytoestrogens.\Question: Choose the right answer from options given a) ten b) zero c) eight d) five

d