The correct option is C Insolvent
One word that can be substituted for the phrase ''A person who has no money to pay off his debts" is option D, insolvent. Option A, Debtor is the person that owes money. Option B 'Pauper' is a very poor person. Option C 'Beggar' is a person who is usually homeless and asks others for money or food. Thus, options A, B and C are incorrect and option D, Insolvent is the correct word for the phrase.