单项选择题

A.fread(unsignedsize,unsignedn,char*buffer,FILE*fp)
B.fread(char*buffer,unsignedsize,unsignedn,FILE*fp)
C.fread(unsignedsize,unsignedn,FILE*fp,char*buffer)
D.fread(FILE*fp,unsignedsize,unsignedn,char*buffer)