string inputFile ="file.drc";            
using (Image image = Image.Load(inputFile))
{
    // Initialize  PdfOptions class object
    PdfOptions options = new PdfOptions();
    
    CadRasterizationOptions cadRasterizationOptions = new CadRasterizationOptions();
    
    cadRasterizationOptions.PageHeight = 500;
    cadRasterizationOptions.PageWidth = 500;
    
    options.VectorRasterizationOptions = cadRasterizationOptions;

    // Export DRC to PDF
    string outPath = "output.pdf";
    image.Save(outPath, options);
}