The given Bar Graph presents the sales of the number of books (in thousands) by six branches of publishing company during two consecutive years 2000 and 2001.The ratio of total sales by branches B1, B3 and B5 for both the years to total sales by branches B2, B4 B6 for the years is:

• A. 47 : 56
• B. 56 : 47
• C. 23 : 21
• D. 21 : 23