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Which is equivalent to:

$$\left(\frac{x^2+y^{-2}z^{7}}{y^{4}z^{3}}\right)^0?$$

$\left(\cfrac{x^2}{y^4z^3}+\cfrac{z^4}{y^6}\right)$

$\cfrac{x^2z^4}{y^6}$

$\cfrac{x^2+z^4}{y^6}$

$1$

None of these