Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to

indicate the correct answer to each of the questions from 43 to 50.

(1) Footracing is a popular activity in the United States. It is seen not only as a competitive sport but also as a way to exercise, to enjoy the camaraderie of like–minded people, and to donate money to a good cause. Though serious runners may spend months training to compete, other runners and walkers might not train at all. Those not competing to win might run in an effort to beat their own time or simply to enjoy the fun an exercise. People of all ages. From those of less than one year (who may be pushed in strollers) to those in their eighties, enter into this sport. The races are held on city streets, on college campuses, through parks, and in suburban areas, and they are commonly 5 to 10 kilometers in length.

(2) The largest footrace in the world is the 12 kilometer Bay to Breakers race that is held in San Francisco every spring. This race begins on the east side of the city near San Francisco Bay and ends on the west side at the Pacific Ocean. There may be 80,000 or more people running in this race through the streets and hills of San Francisco. In the front of are the serious runners who compete to win and who might finish in a little as 34 minutes. Behind them are the thousands who take several hours to finish. In the back of the race are those who dress in costumes and come just for fun. One year there was a group of men who dresses like Elvis Presley, and another group consisted of the firefighters who were tired together in a long line and who were carrying a firehose. There was even a bridal party, in which the bride was dressed in a long white gown and the groom wore a tuxedo. The bride and groom threw flowers to bystanders, and they were actually married at some point along the route.

The phrase “a good cause” in paragraph 1 could be best replaced by which of the following?

Many lives were saved _____ the introduction of antibiotics.