Congress/Carrot Grass is
Parthenium hysterophorus
Parthenium hysterophorus is a species of flowering plant belonging to family Asteraceae. It is commonly known as carrot grass, congress grass, Santa Maria, white top weed etc. It is native to American tropics and is a common invasive species in India, Australia and parts of Africa. The plant produces chemicals that suppress crop and pasture plants leading to the disastrous loss. So, the correct answer is 'Parthenium hysterophorus'.