Biotechnology companies have invested millions

If we know our idioms, we should recognize that we "invest in" something, not "invest into" or "invest for". So we can eliminate down to D and E.

Looking between the two answers, we see that in E, we are comparing the blue rose to "any previous genetically-engineered flower", while in D, we are comparing the blue rose to "any that was previously genetically engineered" ... "any" what? Any blue rose? Any other color rose? The word "flower" doesn't show up anywhere else in the sentence, so "any" can't refer to "flower". This means that E is 1) ambiguous and 2) changes the intended meaning of the sentence. Similarly, the phrase "in research for attempting to create" is less clear and concise than "in research to attempt to create". We can eliminate E and pick D.

If we didn't know the idiom "invest in", we can rule out A, B, and C for other reasons as well. In A, "those" can't refer to "flower", so the meaning is ambiguous and changed. In B, we have "for attempting to create" again in addition to a really strange sentence structure. In C, we are doing research "for the blue rose", not for the purpose of creating the blue rose, which doesn't make any sense.