Let f be a function defined on the interval [0, 1] as \(f(x)=\left\lbrace \begin{matrix} 0, \ \text{if} \ x \ \text{is rational} \\\ 1, \ \text{if} \ x \ \text{is irrational}\end{matrix}\right.\) Then f is -
1
Not R - integrable on [0, 1]
2
R - integrable on [0, 1]
3
May or may not be R - integrable on [0, 1]
4
None of these