Urban development is the major cause of biodiversity loss because of constructions of building, roads, dams etc. in course of a developing urban area requires the removal of forests, natural aquatic and terrestrial ecosystems which are rich sources of biodiversity. As, forest or natural habitat are removed floral species get wiped out and faunal species move to other location, therefore, biodiversity of a region get lost.
Answer: d. The sparrow population decreased because of habitat destruction.
You included no graph but this should be the correct answer.
Habitat loss is one of the leading ways that an animal can go extinct. This happens because the animal has to go to other habitats which might be too dangerous or they eat less because food is not as available as it was in the previous habitat. Habitat loss therefore reduces the population of animals.
This will be no different for the sparrow population here. The large shopping mall has taken the land of the sparrow and now the sparrows will see their numbers decline as time goes on due to a lack of habitat.