Hi Yogesh,
The passage says there was a substantial increase in exports when the currency value decreased. So politicians are asking the government to decrese the value of the currency so they the exports wil again rise.
The question is asking you 2 choose a option which if happened would cast serious doubts on the claim of the politicians.
Option C ssays that ... The exposts have almost reached a peak . this means that even if the currency value was decreased the substantital growth in exports wil not be there ..
Regards,
Vignesh