Select the RTN statement that will be executed for each of the following control strings:

a) P₄ P₃ M_R

MAR <-- PC or AC <-- AC + MBR or MAR <-- MBR or MBR <-- M[MAR] or MAR <-- X

b) P₀ P₁ P₂ P₃

MAR <-- PC or AC <-- AC + MBR or MAR <-- MBR or MBR <-- M[MAR] or MAR <-- X

c) P₅ A₀ L_alt

MAR <-- PC or AC <-- AC + MBR or MAR <-- MBR or MBR <-- M[MAR] or MAR <-- X