Score Plus

Look at the statement again. The conclusion is about imposition of stricter air pollution control rules in other major cities. And how does the author validate the conclusion? By giving an example that strict air pollution controls in London have yielded positive results as the number of bird species in and around the city has increased dramatically - this forms the premise. So certainly there is an assumption that stricter regulations on air pollution will result in cleaner air thereby inducing an atmosphere for birds to breed. By mentioning the cause of air pollution regulation to the effect of increase in birds, the author feels that the proliferation of birds is certainly desirable.

Its only option (a) which seems to have no bearing on the conclusion. I think its still option (a) which is a better option than (d).
Do let me know what do you think abt the analysis.