$$999\,\frac{1}{7} + 999\frac{2}{7} + 999\frac{3}{7} + $$$$999\frac{4}{7} + $$$$999\frac{5}{7} + $$$$999\frac{6}{7}$$is simplified to-

• A. 997
• B. 979
• C. 994
• D. 997