Correct option (C) Both the sentences can be made correct by interchanging the underlined words.
Explanation:
Sentence 1 is correct :
This option is wrong because the word 'ingenuous' means 'frank and simple' which is inappropriate.
Sentence 2 is correct :
This option is also wrong because the word 'ingenious' means 'clever or prudent' and this is inappropriate.
Both the words, i.e. 'ingenuous' and 'ingenious' if interchanged together respectively, it really makes both the sentences meaningful. Hence, appropriate option.
Both the sentences can't be interchanged.
This is an incorrect option because words have been misinterpreted together.
Incorrect option.