Received a PM asking me to respond. In future, please give us an idea of what you do understand and ask very specific questions about what you don't understand. (I'm telling you this for your own good, not because it makes things any easier for me. You'll learn better if you push yourself to articulate what you do and don't understand.)

First, this problem is from the Minor Questions chapter and represents a pretty rare question type: restate the conclusion. Perhaps one in 20 or 30 test-takers will see this type of question on the test - so don't worry about it too much if you are confused by this type.

Read the Q stem first: apparently there's some kind of changing attitude in the argument. I need to figure out what that changing attitude is. Then I need to find something in the answers that "defines" or restates that changing attitude.

Before: PEIs wanted exclusive rights to investments.
Now: PEFs often invest in groups
Why? b/c more competition and larger investments
(I think I've found my "changing attitude" already: they used to want to invest solo and now they want to invest in groups, for the reasons stated in the "Why?" row above.)
"Clearly" investors do this to spread risk and to get more investments. (Ah, so here are some additional "Why?" reasons for the changing attitude.)

The answers represent "statements by a private equity investor" or an investor. They're the ones with the "changing attitudes" described above, so I basically need to find something that a person with this "changing attitude" would say.

A) The argument does mention competition, but it doesn't say that they want to find out their competitors' strengths and weaknesses; instead, it says they want to spread risk and get more investments.
B) The argument does mention competition, but doesn't say anything about wanting to "keep up with our competition."
C) The argument does mention the desire to "gain access to a broader range" of things. The argument also mentions increased competition and that these competitors do sometimes work together. So the motivation (the first half of the answer) is correctly described, and the means (the second half of the answer) is also correctly described.
D) The argument mentions only the desire to "spread some of the risk"; it does not mention the avoidance of all risks in general.
E) This one sounds nice in the real world, but it doesn't reflect the "changing attitude" discussed in the argument. The major point of the "changed attitude" is that the competitors sometimes work together now.

mission's got it. If we say that these investors "often" join up with their competitors, then it's okay to say that investors should expect to do this at least some of the time (or "on occasion").

In this usage "on occasion" is a synonym for "occasionally" or "every once in a while."