Section 80C and 80TTB

Hello 

For my parents I.T return a.y 20-21 who are above 60 years of age, I had claimed 1.5 lakh deduction under section 80c for 5 year time deposit and 50,000 interest income for bank FDS and savings account interest under section 80TTB. But the income tax official disallowed the deduction under section 80TTB saying both 80C and 80TTB deductions cannot be claimed simultaneously. Can you please guide me if this is true ?

Thank you