જો $\tan x = \frac{2b}{a - c}$ $(a \ne c)$,$y = a \cos^2 x + 2b \sin x \cos x + c \sin^2 x$ અને $z = a \sin^2 x - 2b \sin x \cos x + c \cos^2 x$ હોય,તો:

• A
  $y = z$
• B
  $y + z = a + c$
• C
  $y - z = a + c$
• D
  $y - z = (a - c)^2 + 4b^2$