Specifically methylates the cytosine at position 967 (m5C967) of 16S rRNA. cytidine(967) in 16S rRNA + S-adenosyl-L-methionine = 5-methylcytidine(967) in 16S rRNA + H(+) + S-adenosyl-L-homocysteine Belongs to the class I-like SAM-binding methyltransferase superfamily. RsmB/NOP family.