The investigation probably lasted:

Choices:
A. A longer time than the press conference
B. Long enough time to find the evidence
C. Several months to a year
D. not enough information
Several months to a year
Outside the White House Friday, a media frenzy.
And at the center of it all, President Donald Trump.
“Can we do one question at a time? Wait! One question at a time," the president scolded reporters.
Trump launched a new attack on the Russia probe in the wake of a critical report on the Hillary Clinton email investigation by the inspector general of the Department of Justice.
“I did nothing wrong. There was no collusion. There was no obstruction," he said. "The IG (inspector general) report yesterday went a long way to show that, and I think that the Mueller investigation has been totally discredited.”
But the report in question only dealt with how the FBI handled the Clinton email controversy.
It was critical of the man Trump fired as FBI director, James Comey, but rejected the notion of a politically-directed effort aimed at Trump.
“This report did not find any evidence of political bias or improper considerations actually impacting the investigation under review," announced current FBI Director Christopher Wray.
Democrats also took note of the report.
“Anyone who is hoping to use this report to undermine the Mueller probe or prove the existence of a ‘deep state’ conspiracy against President Trump will be sorely disappointed," Senate Democratic leader Chuck Schumer said.

During his lengthy encounter with reporters Friday, Trump also defended his recent summit meeting with North Korean leader Kim Jong Un.
“They are doing so much for us, and now we are well on our way to get denuclearization," he said. "And the agreement says there will be total denuclearization. Nobody wants to report that. I got along with him great. We have a great chemistry together. That is a good thing, not a bad thing."
Trump also lashed out at opposition Democrats and tried to blame them for recent administration actions to separate family members caught trying to come across the U.S. border.
“The Democrats forced that law upon our nation. I hate it. I hate to see separation of parents and children," Trump said.