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').

Female bilbies have a backward-opening pouch with ____ nipples.\Question: Choose the right answer from options given a) no b) two c) five d) eight
d

Intensity is defined as the average of the extreme anomalies during ____ consecutive months.\Question: Choose the right answer from options given a) ten b) three c) two d) five
b

Dengue has an incubation period of five to ____ days after one is bitten by an infected mosquito.\Question: Choose the right answer from options given a) six b) no c) two d) seven

d