For a distribution in the exponential family, E[Y] equals negative derivative ratio - c'(θ) / b'(θ).

• A. E[Y] = c'(θ) / b'(θ)
• B. E[Y] = b'(θ) / c'(θ)
• C. E[Y] = - c'(θ) / b'(θ)
• D. E[Y] = θ

Answer: (C)