Choose from options: Determine if the sentence is true based on the text below:
The man died of natural causes

A body was found Sunday morning under a U.S. Highway 101 overpass at Bay Shore Boulevard near Potrero Avenue in San Francisco, police said. The body of a 56-year-old man was found at 8:37 a.m. Police said there was no sign of foul play and the San Francisco medical examiner is investigating the death.
Available choices: - Yes. - It's impossible to say. - No.
It's impossible to say