Answer: Whoever believes in God's One and Only Son, Jesus Christ, shall have eternal life, (verse 16).
MORE INFORMATION AND/OR OTHER SCRIPTURE REFERENCES:
This also includes a belief on the One Who sent Jesus--God the Father.
John 5:24: [Jesus said,] "I tell you the Truth, whoever hears My Word and believes Him Who sent Me has eternal life and will not be condemned; he has crossed over from death to life."
