If p + q + r = 0, then what is z^{\frac{p^2}{qr}} \times z^{\frac{q^2}{rp}} \times z^{\frac{r^2}{pq}} equal to ?

  1. A. 1
  2. B. z
  3. C. z^2
  4. D. z^3

Correct Answer: D. z^3

Explanation

The expression simplifies to z^{\frac{p^3+q^3+r^3}{pqr}}. Since p+q+r=0, the identity p^3+q^3+r^3=3pqr applies. Thus, the exponent becomes 3pqr/pqr = 3, yielding z^3.

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