From the accounts of the Lord's Prayer in Matthew and Luke, we might reasonably conclude the following:
Jesus used the Lord’s Prayer as an example more than once.
This conclusion is supported by the fact that the two accounts in Matthew (Matthew 6:9-13) and Luke (Luke 11:2-4) differ slightly in wording and context, suggesting that Jesus may have taught the prayer in different settings or to different audiences. It indicates that the essence of the prayer was important enough to be reiterated by Jesus in various circumstances.
The other options, such as the notion that God only answers prayers based on one version, or the claim that one account correctly quotes Jesus while the other does not, oversimplify the relationship between the two accounts and do not accurately reflect scholarly understanding of text variations. Lastly, dismissing the reliability of the New Testament entirely is not a reasonable conclusion based solely on the differences in the Lord's Prayer accounts.