If the roots of the equation $ax^2 + bx + c = 0$ are $l$ and $2l$,then:

  • A
    $b^2 = 9ac$
  • B
    $2b^2 = 9ac$
  • C
    $b^2 = -4ac$
  • D
    $a^2 = c^2$

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