It’s the second choice.
The domain is all the possible x values of a function. So it’s from -4 to 6 because any x value not between those isn’t part of the function f(x). It’s only part of the function IF x meets the conditions they provided.
In interval notation [ or ] means including the number. And ( or ) means excluding the number. So [-4, 6) means the statement “the interval from -4 to 6, including -4 but not including 6”. And it is [-4, 6) because it says “x is less than or equal to -4” (so include) and “x is less than 6” (exclude).
