Which of the following axis system is being satisfied by monoclinic crystal system?

• A. a = b = c, α = β = 90o ≠ ϒ
• B. a ≠ b = c, α = β = ϒ = 90o
• C. a ≠ b ≠ c, α = β = 90o ≠ ϒ
• D. a = b = c, α ≠ β = ϒ = 90o