ANSWER
a) 0
Step-by-step explanation
Clarification: this question asks how many x-intercepts this function has, which is not the same as zeros.
A zero is the solution to f(x) = 0, which can be either a real number or a complex number. If the zero is a complex number, it means that the graph of the function does not actually intersect the x-axis - this is an x-intercept.
In summary, a zero is an x-intercept only if the zero is real. If it is not real, then it is not an x-intercept.
Now, let's solve this. To find the x-intercepts we have to solve f(x) = 0,

Since we have two factors, the function will be zero if any of the factors are zero, so,

To solve this we have to subtract 1 from both sides and take the square root,

Since the value under the radical is negative, the solution is not real, so there are no x-intercepts regarding this factor.
Let's solve the other factor,

The same process: subtract 2 and take the square root,

Again, the value under the radical is negative and, therefore, the solution is not real either.
In summary, this function has four zeros, but the four of them are complex - i.e. not real. Hence, this function has no x-intercepts.