The correct answer is C. Stack.
A stack is a data structure that stores data in a last-in, first-out (LIFO) order. This means that the last item added to the stack is the first item to be removed. Stacks are often used to implement subroutine calls, as well as to keep track of the order of operations in a program.
A PROM (programmable read-only memory) is a type of memory that can be programmed once, but cannot be erased or rewritten. PROMs are often used to store firmware, which is the software that controls the hardware of a device.
A buffer is a temporary storage area that is used to hold data while it is being transferred from one location to another. Buffers are often used to improve the performance of a system by reducing the number of times that data needs to be read from or written to a slower device.
RAM (random-access memory) is a type of memory that can be accessed randomly, meaning that any location in memory can be accessed without having to read through the preceding locations. RAM is often used to store data that is currently being used by a program.
E is not the correct answer because it is not a type of memory.