Option c is correct answer.

Explanation:
A. setTimeout (formatName(), 5000, "John", "BDoe");

This option immediately calls formatName and passes its result to setTimeout, which is incorrect.
B. setTimeout ('formatName', 5000, 'John", "Doe');

This option passes a string 'formatName' instead of a function reference, which is incorrect syntax.
C. setTimeout(() => { formatName("John", "Doe") }, 5000);

This option correctly uses an arrow function to delay the execution of formatName with the given arguments for five seconds.
D. setTimeout (formatName('John', 'Doe'), 5000);

This option immediately calls formatName and passes its result to setTimeout, which is incorrect.