Given the task definition, example input & output, solve the new input case.
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').
Example: Female snakes incubate eggs inside of their bodies, giving birth to live young of ____ or more. \Question: Choose the right answer from the options given a) five b) zero c) seven d) ten
Output: d
Snakes give birth to minimum ten young ones so ten is a correct answer.

New input case for you: Parallel transfer is the simultaneous transmission of the ____ bit-voltages that constitute a byte.\Question: Choose the right answer from options given a) five b) zero c) eight d) ten
Output:
c