Given the Target and Argument texts detect the stance that the argument has towards the topic. There are three types of stances "in favor", "against", and "neutral". 
One example is below.
Q: Topic: Three Gorges Dam
 Argument: The Three Gorges Dam is a cause of corruption.
A: against
Rationale: Here, argument is against the given topic, three gorges dam. Hence, the answer is "against".
Q: Topic: Solar energy
 Argument: The recovery/payback period can be very short.
A:
in favor