Step 1: Understanding the Sentence
This is a well-known proverb about resilience. The first blank needs a form of the verb "fall" to fit the structure "not in never ________". The second blank needs a word to complete the phrase "________ time we fall".
Step 2: Evaluating the Options
After the preposition "in" and the adverb "never", a gerund (the -ing form of the verb) is required. The phrase is "not in \textit{the act of} never falling". So, the first blank should be "falling".
The second part of the sentence is "but in rising ________ time we fall". The meaning is that we rise each time we fall. The word that fits this meaning is "every". The phrase is "every time we fall".
Let's check the options based on this analysis:
(A) fall, more: Incorrect form for the first blank.
(B) falls, only: Incorrect form for the first blank.
(C) falling, every: This fits both blanks perfectly. "not in never falling" and "rising every time we fall".
(D) fell, more: Incorrect form for the first blank.
Step 3: Final Answer
The grammatically correct and meaningful words for the blanks are "falling" and "every". Therefore, option (C) is the correct answer.