The format of a double operand instructions of a cpu consist of $4$ bit opcode and $4$ bit for source and destination.$12$ double operand instructions and $24$ single operand instructions must be implemented.Opcode field must identify the three groups of $n-$ operand instructions .what is the total no. of zero operand instructions that can be implemented?
- $512$
- $516$
- $521$
- $523$