Fill in the blank in the given sentence to complete it logically and correctly:
Indeed, the hold of competition on man exists not alone in his feeling of rivalry towards others; it is evidenced also in the excitement he immediately feels in the presence of ___________ struggle, even though he himself has little or no personal stake.
a) Unpredictable
b) Epic
c) Competitive
d) Rash

Hint: For the above passage (the given sentences in the question) we need to choose an adjective that modifies the noun "struggle". Adjectives are words that describe the qualities or states of being of nouns.

 Complete answer:
The above-given passage ( the sentences are given above in the question) focuses on man and the hold that the competition has on a man. It implies that the man feels a certain kind of excitement when he is presented with a struggle. Now, to understand what would complete the above-given sentence. So, let us look into the options that we have and understand their meaning.
Now as per the options we can understand -
Option (a) – unpredictable: means something (or someone) that cannot be predicted or changed. For example: that was an unpredictable coincidence.
Option (b) – epic: means heroic or grand in scale or character. For example: that was an epic excuse that you told the boss.
Option (c) – competitive: shows the rivalry or competition between peoples. For example: that was a competitive struggle that you had with him to win the competition.
Option (d) – rash: means acting hastily or done without careful consideration without considering the possible outcome. For example: that was a rash decision.
Now, the only option that provides a meaning to the sentence is option (c), i.e. competitive. A competitive struggle means the struggle between two or more people competing in some competition where they are rivals.
So, the correct solution would be option (c), it completes the sentence (passage) as - Indeed, the hold of competition on man exists not alone in his feeling of rivalry towards others; it is evidenced also in the excitement he immediately feels in the presence of competitive struggle, even though he himself has little or no personal stake.

Note:
 Here, the last option is totally irrelevant as rash has nothing to do with struggle or competition but is related to anger, haste, etc.