The correct option is C in the hope
It is clear that the author wants the person he is writing to, to take some action to improve the tourism. So, the most appropriate answer is D) In the hope. Moreover, the word 'may' in the sentence suggests that a word expressing 'expectance' is required. In this light, 'desiring' would be too strong to use with a word like 'may'. Hopeful is an adjective, so is incorrect in the blank.