Hello Sir,
1. No. Tenant A cannot issue Rent Receipt to Tenant B or C, as he is not the rightful owner nor is there an agreement for Subletting.
2. No. The Rent amount is not taxable in the hands of Mr. A, as he is just the intermediary who collects the amount and transfers the same. (But if Mr.A, claims the whole amount as his rent i.e the total amount of Rs.29,000/- then the share of Mr. B & Mr.C will be taxable in his hand under the head Income from Other Sources.
Feel Free to get back for any further clarifications.
Thanking You.
Regards,
CA Rohit R Sharma
CA, LLB - Gen, FAFP, BCOM