Another possibility is that it is for individuals to decide right and wrong for ourselves based on our own personal opinions. The difficulty with this approach is that opinion is no guarantee of correctness. Just because I say something is right does not mean that it is. Others may disagree.
The Bible offers up a completely different approach. It teaches that as the creator of heaven and earth and the one who gives us “life and breath and all things” it is God who decides what is right and wrong for all time. As those who are created it is our duty to listen and obey; this is, in fact, the very purpose of our existence. People who do right (as defined by Him) will be rewarded with eternal life in His Kingdom to come.
Ultimately the answer we make depends on our personal faith. If we consider the evidence and conclude that God exists then we will be inclined to believe He is the arbiter of right and wrong and live in hope of the promised reward.
To watch a presentation which explores this question further, go to our channel on YouTube ('Gorseinon Christadelphians'):