In this case, it is given that Mycoplasma pneumoniae lacks cell wall. some antibiotics such as penicillin works by interfering the synthesis of the cell walls. As these microbes do not have cell wall, the penicillin like antibiotics would not work.
In this case, the antibiotics, which interferes with the DNA (deoxyribonucleic acid) formation and replication can work. The ciproflaxin is an antibiotic, which work by inactivating the enzyme required for DNA replication in bacteria. Hence, the antibiotic ciproflaxin would be effective for treating the given condition.