We are building a computer that has a memory unit with $32$ bits per word. The instruction set consists of $145$ different operations. All instructions have an opcode and a single address $($like Marie$).$ Each instruction is stored in one word of memory.

a$.$ How many bits are required for the opcode?

b$.$ In decimal $($i$.$e$.,$ base $10),$ what is the largest memory address that can be referenced by a computer using this instruction set?

c$.$ In decimal what is the value of the largest negative two$$s complement integer than can be stored in one word of this memory $($by largest, we mean the negative integer with the greatest absolute value$)?$