All bridges built from 1950 to 1960 are in serious need of rehabilitation. Some bridges constructed in this period, however, were built according to faulty engineering design. That is the bad news. The good news is that at least some bridges in serious need of rehabilitation are not suspension bridges, since no suspension bridges are among the bridges that were built according to faulty engineering design. If the statements above are true, then, on the basis of those statements, which one of the following must also be true? ['Some bridges that were built according to faulty engineering design are not bridges other than suspension bridges.', 'Some bridges that were built according to faulty engineering design are in serious need of rehabilitation.', 'Some suspension bridges are in serious need of rehabilitation.', 'Some bridges built from 1950 to 1960 are not in serious need of rehabilitation.']