请教逻辑题

qsxx1925

请教一道题:

At the turn of the twentieth century, forest covering as much as 90 percent of Thailand and accommodating as many as 300,000 elephants, a third of them domesticated and performing various essential tasks.

• A. covering as much as 90 percent of Thailand and accommodating as many as 300,000 elephants, a third of them
• B. covering as much as 90 percent of Thailand accommodated as much as 300,000 elephants, and a third of them were
• C. covered as much as 90 percent of Thailand and accommodated as much as 300,000 elephants, with a third
• D. covered as much as 90 percent of Thailand and accommodated as many as 300,000 elephants, a third of them
• E. covered as much as 90 percent of Thailand and accommodating as many as 300,000 elephants, with a third of them
  

答案远D. 不理解其中一个语法点，最后句尾的performing是什么语法功能?

qsxx1925

这是语法题，发错啦，已转语法区