Section 80ccd

Basic salary of mr A is ₹20000 pm . He is entitled to dearness allowance which is 40% of basic salary. 50% of dearness allowance form part of pay for retirement benefit. Both mr A & his employer contribute 15% of basic salary to the person scheme referred to in section 80CCD. Explain tax treatment in respect of such contribution in the hand of MR A. please answer this question I am confusing in this question. I m getting diff answer from book