Consider the reaction ,$2A +B \to products$ when concentration of B alone was doubled , the half -life did not change . When the concentration of A alone was doubled, the rate increased by two times. The unit of rate constant for this reaction is :

Question

$(a)\;L\; mol^{-1}S^{-1} \\ (b)\;\text{No unit} \\(c)\;mol\;L^{-1}\;S^{-1} \\(d)\;S^{-1}$