Which concept describes selections or loops inside each other?

• A. Nested statements
• B. Library routines
• C. Global variables
• D. One-dimensional arrays

Answer: (A)

Nesting control structures describes selections or loops inside each other. When you place one control structure inside another—such as a loop inside a loop or a conditional inside a loop—you create nested statements. This lets you perform actions at multiple levels of decision or repetition.

For example:

for i in range(n):

for j in range(m):

if grid[i][j] == 1:

process(i, j)

In this case, the inner loop and the if statement are inside the outer loop, so they execute for every combination of i and j. That’s nesting in action.

The other ideas refer to things like prewritten functions (library routines), data that can be accessed from anywhere in the program (global variables), or a simple list of values (one-dimensional arrays). They aren’t about putting control flow inside other control flow.