Q.Checking a user's input at the front-end — for example, refusing a blank name or a negative age — before it is sent to the database is called:

The question describes guarding the data by checking input before it reaches the back-end.

Validation is the front-end's job of checking the user's input before it is sent to the back-end — confirming that required boxes are filled, that a number field really holds a number in a sensible range, that a date is valid, and so on. It keeps wrong or incomplete data out of the database and gives the user an immediate, friendly message.

Option-by-option analysis:

• (a) Encryption scrambles data for security; it does not check input for correctness.
• (b) Validation is correct — checking input for completeness and correctness. …

Confusing validation (checking input is correct) with encryption (protecting data by scrambling it). They …