question_answer

Which of the following is the empty set

A)  {x: x is a natural number and \[{{x}^{2}}-1=0\]}

B)  {x: x is a natural number and \[{{x}^{2}}+1=0\]}

C)  {x: x is a an integer number and \[{{x}^{2}}-9=0\]}

D)  {x: x is a an integer number and \[{{x}^{2}}=x+2\]}

E)  None of these