25ml of 3.0M $HNO_3$ are mixed with 75ml of 4.0M $HNO_3$.If the volumes are additive,the molarity of the final mixture would be :

Question

$(a)\;3.25M\qquad(b)\;4.0M\qquad(c)\;3.75M\qquad(d)\;3.50M$