Explanation:

*Parthenium hysterophorus*, commonly known as carrot grass or congress grass, is an invasive weed notorious for causing severe allergic reactions in humans and livestock. Its pollen is a major allergen, leading to respiratory problems like asthma, bronchitis, and allergic rhinitis, as well as skin conditions like contact dermatitis. - Option A (Krishna Neel): *Krishna Neel* (Ipomoea nil) is a flowering plant, but it is not primarily known as a major cause of asthma. - Option B (Bathua): *Bathua* (Chenopodium album) is a common weed, often consumed as a leafy vegetable, and is not typically associated with causing asthma. - Option C (Parthenium): *Parthenium hysterophorus* is widely recognized as a significant cause of allergic asthma and other allergic reactions due to its highly allergenic pollen. This is the correct answer. - Option D (Hiran Khuri): *Hiran Khuri* (Convolvulus arvensis or Field Bindweed) is a common agricultural weed but is not known as a primary cause of asthma.