The bus ---- is along the road .Look!A bus --- there.

The bus ____ is along the road .Look!A bus ___ there.
A..stop；stopped B..stop ；stopping
C..stoping;is stoping C..stop ;is stopping
希望能有较准确的解释 ...
补充下。朋友暑假做家教。来问的，标准答案是A..我们几个都选了D。然后几个大学生死在这题上了。请达人给个确切答案及解释。