1. If you look at the context there...
"Itís been a wonderful evening.Thank you very much" (It showed that this person wants to say thank you. So normally, my pleasure or your welcome is the best answer for this kind of expression.
2. Why not B...
Look, if someone want to say 'thank you' I think it's a bit queer if you reply:
"Iím glad to hear that" It does sound a bit chesty to me... Don't you think so?
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