Answer: Jesus is the exact representation of God's being, (verse 3).
MORE INFORMATION AND/OR OTHER SCRIPTURE REFERENCES:
To understand "exact representation," look up the word "image" in the Glossary.
Jesus is not merely an image, or reflection, of God. Because the Son Himself is God, He is the absolutely authentic representation of God's being:
John 14:9-10: "Jesus answered: ‘Don't you know Me, Philip, even after I have been among you such a long time? Anyone who has seen Me has seen the Father. How can you say, "Show us the Father"? Don't you believe that I am in the Father, and that the Father is in Me? The Words I say to you are not just my Own. Rather, it is the Father, living in Me, Who is doing His work.'"
And Colossians 1:15-20 says: "He is the image of the invisible God, the firstborn over all creation. For by Him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things were created by Him and for Him. He is before all things, and in Him all things hold together. And He is the head of the body, the church; He is the beginning and the firstborn from among the dead, so that in everything He might have the supremacy. For God was pleased to have all His fullness dwell in Him, and through Him to reconcile to Himself all things, whether things on earth or things in heaven, by making peace through His blood, shed on the cross."