The criminal law of our country stipulates: discontinuance of a crime is an automatic abandonment of the crime or an automatic and effective prevention of its consequences in the criminal activity.
According to the above definition, which of the following is the discontinuance of a crime?
A sneaked into B's house while B was asleep and wanted to kill B. After turning on the gas valve for a while, he regretted it. Then he closed the gas valve and called the hospital to rescue B. Then B escaped.