Study the following tables carefully and answer the questions that follow.
There are 6 refineries, 7 depots, 9 districts. The refineries are BB, BC, BD, BE, BF, BG. The depots are AA, AB, AC, AD, AE, AF and AG and the districts are AAA, AAB, AAC, AAD, AAE, AAF, AAG, AAH, AAI.
Table A shows the cost of transporting one unit from refinery to depot.
Table B shows the cost of transporting one unit from depot to districts.
How many possible ways are there for sending one unit from any refinery to any district?
- $63$
- $42$
- $54$
- $378$