Which of the following is INCORRECT?

Let's check each statement:Option A: True, $x\times 1=x$ for any rational number.Option B: True, $a+b=b+a$ for all natural numbers.Option C: Incorrect. Rational numbers include fractions like $\frac{1}{2}$ or negative quotients like $-\frac{3}{4}$, which are clearly not whole numbers ($0,1,2,3\dots$).Option D: True, $\frac{1}{1}=1$.