Question

In the vars assignment block, ________ refers to the value of an externally defined variable low.

(a) “$$low”

(b) “$$lowin”

(c) “$$1”

(d) None of the mentioned

I have been asked this question by my school teacher while I was bunking the class.

The above asked question is from Aggregation Mechanics topic in portion Aggregation Concepts and Aggregation Mechanics of MongoDB

Answer 1

Correct choice is (a) “$$low”

The best I can explain: If low is not defined outside this $let expression block, the expression is invalid.