Dear Raj
This year you will debit the Capital/Drawings A/c and make the loan to person B. And you can keep a note or sub-schedule showing the break up details of the drawings which will include the above interest free loan. Later, when person B repays the loan to you, you can either re introduce the capital by crediting your Capital/Current A/c if the same is needed in your business capital or you can choose to keep it in your personal bank account (which is not used for business pruposes).
If you choose to reintroduce the capital, then your explanation for the source will be repayment from the person B towards the loan advanced in earlier year evidence of which will be the said note or sub-schedule you have prepared in the year of advancing the loan.
Or , if you choose to keep it in your personal bank a/c, say your savings a/c, it will reflect in the cash flow prepared for your personal return, evidence of which again will be the said note or sub-schedule you have prepared in the year of advancing the loan.
At the time of repayment of the loan, it is not an income for you. It is not a gift to you from person B, neither any "income" is earned by you being the repayment of the principal portion of the interest free loan. If you had advanced a interest bearing loan, then you would have had offered the interest for taxation.
The basic thing is the balance sheet in the ITR 4 is for the Balance Sheet of your business.
Regards
Ajay