Given the task definition and input, reply with output. 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. Among the entities, try to find the best entity that is most likely to fill in "_" and classify the answers based on options.

We're not bluffing, the Obama administration told Afghanistan on Tuesday in announcing for the first time it has started planning for the possible withdrawal of all U.S. troops by the end of the year if no security agreement is signed. Statements by the White House and Defense Secretary Chuck Hagel showed President Barack Obama's impatience with Afghanistan President Hamid Karzai's refusal to sign the agreement that would keep several thousand American troops in the country after combat operations conclude this year. In a phone call with Karzai on Tuesday to discuss upcoming elections for a new Afghan leader, Obama made clear that time was running out to properly plan for keeping any U.S. forces in the country beyond 2014, the White House said.President Obama calls Afghan leader to discuss security agreementObama orders planning for bringing home all U.S. troops at the end of 2014Afghan President Karzai refuses to sign a deal to keep some troops thereThe White House says an agreement could happen after Karzai leaves office in April 
 Questions:The security agreement negotiated between Afghanistan and the United States would cover a continuing mission after 2014 focused on training _ forces and counterterrorism. (A) Obama (B) Afghanistan (C) U.S. (D) White House (E) Chuck Hagel (F) Barack Obama (G) Hamid Karzai (H) American (I) Karzai

(B)