The reported speech is an example of a simple affirmative sentence. Option (d) is the correct answer. Option (a) is ruled out due to the use of ‘our business’ as it should be their business. Option (b) is ruled out as it is in the past indefinite tense, whereas the reported speech in the present perfect tense and it should be converted into past perfect tense. Option (c) is ruled out due to the use of ‘said’ as it should be ‘told’