What is the formula for mₙ in the recursion sequence m₁ = 2 and mₙ = a⋅m₂ₙ₋₁ for n>1? a) mₙ = 2ⁿ⁻¹ b) mₙ = aⁿ c) mₙ = 2ⁿ d) mₙ = a²ⁿ⁻¹