Howmany $$bits$$ wide are the following systems? Why?

$($a$)$ An ARMCortex A$72$ processor $($found in a Raspberry Pi $4$B$).$ Its ALU and registers are $64$ bits.

Its address bus is $44$ bits. Most instructions it executes are $32$ bits long.

$($b$)$ An ARM $1176$ found in the original Raspberry Pi $1$B$.$ Its registers, integer ALU. program

counter, and address bus are all $32-$bits. It executes instructions that are $32$ or $16$ bits long.

$($c$)$ A MOS$6502$ processor $($found in older desktop and embedded systems$).$ Its registers, data bus,

and ALU are $8-$bit while the instruction pointer and address bus are both $16-$bit