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').

Ascidian tunicates come in ____ main forms.\Question: Choose the right answer from options given a) three b) zero c) four d) eight
a

Poisons come in ____ different forms .\Question: Choose the right answer from options given a) four b) no c) five d) ten
a

Deletion mutations involve more than ____ base pairs.\Question: Choose the right answer from options given a) five b) six c) ten d) two

d