The correct answer is (b), Eucalyptus. Eucalyptus trees are not eco-friendly because they are fast-growing and can outcompete native plants, which can lead to the loss of biodiversity. They also have a shallow root system, which can make them susceptible to drought and erosion. Additionally, eucalyptus trees can produce a large amount of pollen, which can be an allergen for some people.
Babul trees (a) are native to India and Pakistan and are known for their drought tolerance and ability to grow in poor soil. They are also a good source of fodder for livestock. Neem trees (c) are also native to India and Pakistan and are known for their medicinal properties. They are also a good source of wood and fodder. Pipal trees (d) are native to India and Southeast Asia and are considered sacred in Hinduism. They are also a good source of wood and fodder.
Eucalyptus trees are native to Australia and were introduced to India in the 19th century. They are now widely planted in India for their timber and pulp. However, eucalyptus trees have been criticized for their negative environmental impact. They are known to outcompete native plants and can lead to the loss of biodiversity. They also have a shallow root system, which can make them susceptible to drought and erosion. Additionally, eucalyptus trees can produce a large amount of pollen, which can be an allergen for some people.