Bartlett's method for scoring sputum and the Murray-Washington method for contamination assessment associate what with unacceptable sputum specimens?

A) 10 to 25 neutrophils/10 $\times$ field
B) Greater than 25 neutrophils/10 $\times$ field
C) 10 to 20 squamous epithelial cells/10 $\times$ field
D) Less than 10 squamous epithelial cells/10 $\times$ field