$(15)$ Consider the memory array with $128K8$ size

a$.(5)$ How many $128K8$ RAM chips are needed to provide a memory capacity of $2M$ bytes?

b$.(5)$ How many lines of the address must be used to access $2M$ bytes? How many of these lines are connected to the address inputs of all chips?

c$.(5)$ How many lines must be decoded for the chip select inputs? Specify the size of the decoder