Answer is C. Both are single celled.
Escherichia coli, commonly called E. coli is a type of bacteria common in human and animal intestines. It is a unicellular, prokaryotic cell, as all bacteria are prokaryotic. It is included in the Kingdom Monera.
Paramecium is also a unicellular or single celled eukaryotic. It is classified in the phylum Ciliophora Kingdom Protista.