Final answer:
The line from the fable that does not help develop the theme of trust is "A fox was once caught in a trap." It simply sets the scene without addressing the theme of trust or deceit.
Step-by-step explanation:
The line from "The Tiger, the Fox, and the Hunters" by Ramaswami Raju that does not help develop the universal theme of 'Be careful of those you have to ask if you can trust' is C. "A fox was once caught in a trap." This sentence merely sets the scene and does not speak to the theme of trust or betrayal. In contrast, the other sentences directly relate to the cunning actions of the fox and the consequences of misplaced trust.
The fox's promise and subsequent betrayal in both A. "I have kept my promise to both; now you may settle it between yourselves." and D. "Sir Tiger, here are the men; gentlemen, here is the Tiger." highlight his deceit and reinforce the theme.
Similarly, line B. "The Tiger exclaimed, when it was too late, 'Alas! what art for a double part!'" reflects on the consequences of the tiger's misguided trust in the fox.