1) Which of the following does not represent a rational algebraic expression?
A.
[tex] \frac{x + 2}{x {}^{2} - 4 {x}^{} + 4 } [/tex]
B.
[tex] \frac{1}{x {}^{3} } [/tex]
C.
[tex] \frac{x {}^{2} }{x {}^{4} - 3 } [/tex]
D.
[tex] \frac{x {}^{3} - 2x - 1 }{3} [/tex]

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