【单选题】

Modern tourism began with the transition from a rural to an industrial society, the rise of the automobile, and the expansion of road and highway systems.Before the Second World War, travel for pleasure was limited to the wealthy, but since then, improved standards of living and the availability of transportation have allowed more people to indulge. In the 1960s, improvements in aircraft technology and the development of commercial jet airlines enabled fast international travel. The tourism industry explodeD、Today, airports in nearly every country can accommodate jumbo jets full of tourists seeking exotic destinations.

The word exploded in the passage is closest in meaning toA．was competitive
B．expanded rapidly
C．was expensive
D．became dangerous