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').

[EX Q]: Many soils have ____ major layers or horizons, top soil, subsoil and parent material.\Question: Choose the right answer from options given a) one b) two c) seven d) three
[EX A]: d

[EX Q]: Most aphthous ulcers heal in one to ____ weeks.\Question: Choose the right answer from options given a) two b) eight c) one d) seven
[EX A]: a

[EX Q]: Vector quantities have ____ characteristics, a magnitude and a direction.\Question: Choose the right answer from options given a) seven b) six c) five d) two
[EX A]:
d