Answer:
The evidence that highlights this conflict is:
b. Sekhar felt greatest pity for him. But he felt he could not help it. No judge delivering a sentence felt more pained and helpless.
d. Two casualties for today, Sekhar said to himself. If I practice it for a week, I don’t think I shall have a single friend left.
Explanation:
As was stated in the question, the conflict in "Like the Sun", by R. K. Narayan, is the fact that Sekhar does not want to hurt people's feelings, but he has decided to tell only the truth for a whole day. Therefore, he knows very well he will end up hurting others. He sticks to his plan and only says what he truly thinks. However, that does not happen without discomfort or pain. He feels for the others, he knows he is insulting them.
The headmaster of the school where Sekhar teaches becomes vindictive after being told his pursuit of music should not go on. Sekhar makes it very clear that he is a terrible singer, but does so with great pain:
Sekhar felt greatest pity for him. But he felt he could not help it. No judge delivering a sentence felt more pained and helpless.
Upon arriving home, Sekhar's wife is sullen after having been told her food tasted bad in the morning. Sekhar confirms what he already had predicted - that telling the truth brings problems in social life since people do not really want to hear it:
Two casualties for today, Sekhar said to himself. If I practice it for a week, I don’t think I shall have a single friend left.
To him, facing the truth is like staring at the sun: no one can really do it.