If C₀, C₁, .... , C₂₀₁₂ are binomial coefficients in the expansion of (1+x)²⁰¹² and a₀, a₁, a .... , a₂₀₁₂ are real numbers in arithmetic progression then value of a₀C₀ - a₁C₁ + a₂C₂ - a₃C₃ + ... . + a₂₀₁₂C₂₀₁₂ is a:
A. Even number
B. Odd number
C. Natural number
D. Prime number