Guess this?

[Snow preck]

This type of JavaScript function is known as:
A. Constructor

B. Scoped

C. Anonymous

D. Self-invoking

I feel Self-invoking correct, Please correct if I am wrong.

[Sandeep Rajput · Accepted solution]

@Snow preck This is a self-invoking function. As it calls itself when the execution of the script field begins. 

[dgarad · Accepted solution]

Hi @Snow preck  

Self-invoking is correct.

[Sandeep Rajput · Accepted solution]

@Snow preck Please accept the response as a solution if I addressed your question. 

[Sandeep Rajput · Accepted solution]

@Snow preck This is a self-invoking function. As it calls itself when the execution of the script field begins. 

[Sandeep Rajput · Accepted solution]

@Snow preck Please accept the response as a solution if I addressed your question. 

[dgarad · Accepted solution]

Hi @Snow preck  

Self-invoking is correct.

[SN_Learn · Accepted solution]

Correct answer is self-invoking

Developers write their code inside the executeRule function. The current and previous objects are automatically passed to the executeRule function.

The function syntax is known in JavaScript as a self-invoking function or an Immediately Invoked Function Expression (IIFE). The function is immediately invoked after it is defined. ServiceNow manages the function and when it is invoked; developers do not explicitly call Business Rule scripts.

ServiceNow reference Document: Self Invoking function 

Please hit like and mark my response as correct if that helps.