The line $x \cos \alpha + y \sin \alpha = p$ will be a tangent to the conic $\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1$,if

  • A
    $p^2 = a^2 \sin^2 \alpha + b^2 \cos^2 \alpha$
  • B
    $p^2 = a^2 + b^2$
  • C
    $p^2 = a^2 \cos^2 \alpha + b^2 \sin^2 \alpha$
  • D
    None of these

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