$($b$)$ An application SQL queries in the following manner:

query $=$ "SELECT $*$ FROM users WHERE id$="+$ userInput

Which technique would best mitigate the risk of SQL injection?

$$

i$)$ Use regular expressions to validate userInput.

ii$)$ Encode userInput to ensure it does not contain SQL meta$-$characters.

iii$)$ Use parameterized queries or prepared statements.

iv$)$ Escape all single quotes in userInput.