Note that E is connected to the 0 marking on the decoder and F to 1. This means that if we look at the truth table to determine the min-terms, E will be in the lowest significant column and F in the higher, i.e., the pair should be read as FE and not EF. Therefore E=0 and F=1 should be read as 10 and not 01 and will correspond to min-term m2. This is why register C gets connected to the bus for E=0 and F=1.