The correct answer is: B. SGST and IGST liability.
The balance in electronic credit ledger under SGST can be used against SGST and IGST liability. This is because SGST and IGST are both Central GST (CGST) and State GST (SGST) taxes. CGST and SGST are levied on the same supply of goods or services, and the taxpayer can claim credit of CGST paid on inputs against the liability of SGST payable on output.
The balance in electronic credit ledger under SGST cannot be used against CGST liability. This is because CGST and SGST are separate taxes, and the taxpayer cannot claim credit of one tax against the liability of another tax.
The balance in electronic credit ledger under SGST cannot be used against IGST liability. This is because IGST is a composite tax that includes CGST and SGST. The taxpayer cannot claim credit of CGST or SGST against the liability of IGST.