Final answer:
Without the context of the original answer for part a, it is not possible to determine the phrase that best supports it from the passages provided.
Step-by-step explanation:
We need to determine which phrase from the given passages best supports the answer to a previous part of a question, presumably about struggle, effort, or the consequences of actions. Options 'a' and 'd' both refer to positive outcomes or honors (“the more glorious the triumph” and “so celestial an item”). Option 'b' (“what we obtain too cheap”) suggests that easy gains may not be valued, while 'c' (“heaven knows how”) implies a lack of understanding or control.
Considering all options, and without the context of part a's specific answer, it is not possible to definitively select the best supporting phrase.