Please answer the following question: Read the following context and choose the correct option to answer the question. Context: Just minutes after Donald Trump fired Rex Tillerson on Tuesday, the president was blunt about his long-standing differences with his former secretary of state. "We disagreed on things," Trump told reporters outside the White House, specifically pointing to friction over the Iran nuclear agreement. "I wanted to either break it or do something, and he felt a little bit differently," Trump said. "We were really not thinking the same." Trump reportedly had considered firing Tillerson for months. But the decision - and the abrupt way it was executed - represents a dramatic end to a strained relationship. Tillerson learned of his firing by an early-morning Trump tweet, according to Steve Goldstein, undersecretary of state. White House officials disputed that notion, and promptly fired Goldstein. The move left some of Trump's staunchest defenders with mixed feelings. "It's all very Trumpian," said James Carafano of the conservative Heritage Foundation, who helped staff the State Department as a member of Trump's transition team. "When the president makes changes, he just abruptly makes them." During his 14 months at the State Department, Tillerson had numerous policy differences with Trump - and the friction frequently played out in public. The animosity peaked in October, when news surfaced that Tillerson reportedly called Trump a "moron" following a July Pentagon meeting. Tillerson never explicitly denied the account. Tillerson also publicly disagreed with Trump's decision to pull out of the Paris climate accord. He reportedly opposed Trump's decision to move the U.S. embassy from Tel Aviv to Jerusalem. And Tillerson sometimes took a tougher stance than Trump on Russia including this week, when he blamed Moscow for a suspected nerve agent attack in Britain. In return, Trump on numerous occasions publicly undermined his top diplomat, including in October when he tweeted Tillerson was "wasting his time" trying to negotiate with North Korean leader Kim Jong Un. When Trump ultimately made his decision last week to... Question: who was negotiating with North Korean leader? Options: - not enough information - Kim Jong Un. - Tillerson - Trump
A:
Tillerson