The most<br/>common pathogen of acute hematogenous osteomyelitis is () A: mould B: pneumonia C: Staphylococcus aureus D: Escherichia coli

5 year old boy, sudden chill. T: 39℃. Right knee pain, did not dare to play, no obvious local swelling, the diagnosis should be first considered: () A: chronic osteomyelitis B: acute hematogenous osteomyelitis C: rheumatoid arthritis D: septic arthritis