For entries involving both cash and bank transactions we use ________ voucher

Answer: Option A

As per the Accounting Principles, a Contra entry is a transaction involving transfer of cash between one Bank / Cash account to another Bank / Cash account, Cash Deposit / Withdrawals into/from Bank.
Contra voucher type is used in tally to transfer amount from one bank to another.
Go to Gateway of Tally > Accounting Vouchers > Select F4: Contra from the Button Bar or press F4 .