public sealed class VersionDescription 

public Version CreateVersion(Geodatabase geodatabase, string versionName, string description, VersionAccessType versionAccessType)
{
    if (!geodatabase.IsVersioningSupported()) return null;

    using (VersionManager versionManager = geodatabase.GetVersionManager())
    {
        VersionDescription versionDescription = new VersionDescription(versionName, description, versionAccessType);
        return versionManager.CreateVersion(versionDescription);
    }
}