Ans: B(Ref: Robbins 9/e p544)Triphenyltetrazolium chloride (TTC) stain:Impas a brick-red color to intact, non-infracted myocardium where dehydrogenase enzymes are preserved.Acute Ml - Early morphologic recognition:Infarct preceding death by 2 to 3 hours:Highlighting area of necrosis by immersion of tissue slices in a solution of triphenyltetrazolium chloride.Gross histochemical stain impas brick-red color to intact, non-infarcted myocardium where lactate dehydrogenase activity is preserved.Dehydrogenases leaks out damaged membranes of dead cells.Hence, an infarct appears as an unstained pale zone.By 12 to 24 hours after infarction:MI identified grossly as a reddish-blue area of discoloration.Caused by stagnated, trapped blood.By 2 days to 10 days:Infarct becomes progressively more sharply defined, yellow-tan & soft.By 10 days to 2 weeks:Rimmed by a hyperemic zone of highly vascularised granulation tissue.Over succeeding weeks:Fibrous scar