C

Reasoning: The serum (1→3)-β-D-glucan assay detects fungi whose cell walls contain abundant β-1,3-glucan. Candida species, Aspergillus species and Pneumocystis jirovecii all have significant β-glucan and frequently give positive results in invasive disease or pneumonia [Obayashi et al., 2008, PMID 18462174; Damiani et al., 2011, PMID 21430107]. In contrast, Mucorales (cause of mucormycosis) have cell walls dominated by chitin/chitosan with minimal β-1,3-glucan, so β-D-glucan tests remain negative even in proven infection [Cui et al., 2022, PMID 35479945]. Therefore the test is positive in all of the listed organisms except Mucormycosis.