Solution

Plant fossils were formed by burial and preservation in the sediments in the geological past. In India, the first fossil plant was recorded in the later part of the eighteenth century, Williamsonia is an extinct genus of a plant belonging to Bennettitales and bore a resemblance to Cycads. Prof. Birbal Sahni revitalized Indian fossil plants and discovered Williamsonia sewardiana which thrived in Rajmahal, Bihar 140 million year ago.
Therefore, the correct answer is option C.