Answer:
A
Step-by-step explanation:
Let's check each of A, B, C, and D.
A. if x > 0, both radicals are defined.
B. if x < 0, the first radical is defined but the second is not (you can't take the square root of a negative number).
C. when x = 0, both radicals are defined but the expression is not (you can't divide by zero).
D. when x < 1, the first radical is defined but the second is not (see B).
The answer is A.
