Like dog's poop on city pavements, rubbish left behind by tourists at natural sites is disgusting.
The funny thing is nobody likes seeing such mess in the places they are visiting but it seems only few really care enough to keep the place tidy. The obvious result is that garbage has become a common sight in forests which attract tourists.
We are certain that in many places park rangers—despite their small numbers, incomparable to the tremendous tourist troops—are already doing the best they can. Sometimes, however, we believe things could still be better.
Take the Thi-Lor-Su waterfall in Tak province for instance. One of the things about Thi-Lor-Su which we would like to talk about today is the commendable method of rubbish control at the waterfall.
There, food and drinks in commercial packaging are prohibited. The ban is enforced by requiring that each and every visitor heading from the camping ground to the waterfall has to pass through a checkpoint where their bags are inspected and potential garbage is seized. The results have been amazing. Despite thousands of visitors, the 1. 5-kilometre trail to Thi-Lor-Su, as well as the waterfall itself, is almost free of garbage.
However, within the same forest, along the 16 kilometers of rough road from the Pha Luead checkpoint to the camping ground, the situation is completely different. Both sides of the road are littered with rubbish, from candy wrappers to Styrofoam food boxes to plastic water bottles.
One contributing factor to the mess is that several tour operators use ordinary pick-up trucks to transport their clients in and out of the forest. The ordinary trucks often get stuck and tourists are forced to walk the rest of the distance—which can be several kilometers. And, as you would expect, there are more inconsiderate tourists than conscientious ones. Along the way, people eat and throw rubbish.
One solution to this problem is to encourage tour operators to use proper vehicles. Either that or put off traveling into the forest until the road is really dry and passable.
How does the writer feel about the fact that people hate to see rubbish but still throw it carelessly？

A. Their behavior. is ridiculous.
B. Their behavior. is immoral.
C. Their behavior. is foolish.
D. Their behavior. is illegal.