Which scenario best justifies the use of MacConkey agar in diagnosis?

Detection of lactose fermentation to differentiate Gram-negative enteric bacteria such as E. coli from non-lactose fermenters like Salmonella

Identifying Gram-positive cocci such as Staphylococcus aureus using selective media enriched for Gram-positive growth

Differentiating fungal pathogens such as Candida albicans from other yeasts in clinical samples

Testing viral infections such as influenza using culture-based diagnostic assays