The correct answer is: A. Repetition
Repetition is a control structure that allows a program to execute a block of code multiple times. This is often necessary when a program needs to perform a task a certain number of times, or until a certain condition is met.
There are several different types of repetition control structures, including:
- For loops are used to execute a block of code a specified number of times.
- While loops are used to execute a block of code as long as a certain condition is true.
- Do-while loops are similar to while loops, but the condition is checked at the end of the loop instead of the beginning. This means that the block of code will always be executed at least once, even if the condition is false.
Selection is a control structure that allows a program to choose between two or more possible paths of execution. This is often necessary when a program needs to make a decision based on some input or condition.
There are several different types of selection control structures, including:
- If statements are used to execute a block of code if a certain condition is true.
- Switch statements are used to execute a block of code based on the value of a variable.
- Ternary operators are used to choose between two expressions based on the value of a condition.
Sequence is a control structure that allows a program to execute a block of code in the order in which it is written. This is the most basic type of control structure, and it is used in every program.
Switching is not a control structure. It is a keyword that is used to create a switch statement. A switch statement is a type of selection control structure that allows a program to choose between multiple possible paths of execution based on the value of a variable.
Therefore, the correct answer is A. Repetition.