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').

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

A: a
****
Q: China has about ____ in four of all smokers in the world.\Question: Choose the right answer from options given a) one b) seven c) ten d) six

A: a
****
Q: Photons have no mass and ____ electrical charge.\Question: Choose the right answer from options given a) no b) seven c) two d) eight

A:
a
****