Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: Washington (CNN) In a rare win for environmentalists since President Donald Trump took office, the Senate defeated Wednesday an attempted GOP-led rollback of an Obama-era methane gas rule. The rule, which was finalized under President Barack Obama in November, would require oil and gas companies to actively plug leaks of natural gas while scaling back their practice of intentionally venting or burning the gas in order to extract more profitable crude oil. The drilling industry, however, supported Republicans' efforts to overturn the rule, saying it would undo the costly regulation, which is viewed as a threat to jobs and operations.Environmentalists get rare win to keep Obama-era regulationRollback of rule aimed to lessen regulations on natural gas producers 
 Question:Environmental groups were primed for the short victory after seeing a number of other departmental regulations overturned or delayed since _ became President.

Donald Trump