To avoid government oversight of file sharing, the company should consider advertising in Germany. Germany has strict data protection laws (such as GDPR), but it does not have the same level of government censorship and oversight concerning file sharing as countries like China, Sudan, or North Korea.
In China, the government highly regulates and monitors internet usage, including file-sharing services. Sudan and North Korea also have significant government control over internet and online activities, which would likely impede the company's ability to operate freely.
Therefore, the best choice from the given options is Germany.