Answer:
Option B: [1, ∞)
Explanation:
The domain of the function would mean the possible numbers you could plug in for x to get y. Looking at the equation we see that there is a square root over x - 1. This means that x - 1 cannot equal a negative number because you cannot do the square root of a negative number. Therefore the lowest x value you could use is 1 because 1 - 1 = 0 and the square root of 0 is a valid answer. There are no other restrictions so the answer is [1, ∞).