Update README.md

Author: Riyakumari57

README.md

@@ -260,7 +260,8 @@ console.log(Greet());
 </ul>
 
 # <li>Optional chaining (?.)</li>
-<p>The ?. operator is like the . chaining operator, except that instead of causing an error if a reference is nullish (null or  undefined), the expression short-circuits with a return value of undefined. When used with function calls, it returns undefined if the given function does not exist.</p>
+<p>The ?. operator is like the . chaining operator, except that instead of causing an error if a reference is nullish (null or  undefined), the expression short-circuits with a return value of undefined. When used with function calls, it returns undefined if the given function does not exist.
+The <b>optional chaining (?.)</b> operator accesses an object's property or calls a function. If the object accessed or function called using this operator is undefined or null, the expression short circuits and evaluates to undefined instead of throwing an error.</p>
 
 
 </ul>