In 2007, Statkraft, a Norwegian state-owned electricity company, was the third largest energy producer in the Nordic region, producing 22.7 kWH of energy of which majority was Hydroelectric produced in 133 plants in Norway, 12 in Sweden and 4 in Finland and, including the subsidiaries Skagerak Energi and Trondheim Energi, which had 2100 employees.

a)In 2007, Statkraft, a Norwegian state-owned electricity company, was the third largest energy producer in the Nordic region, producing

b ) In 2007, Statkraft, a Norwegian state-owned electricity company, was the third largest energy producer in the Nordic region, which produced

c ) The third largest energy producer in the Nordic region in 2007 was Statkraft, a Norwegian state-owned electricity company, producing

d)In 2007, the third largest energy producer in the Nordic region was Statkraft, a Norwegian state-owned electricity company, which produced

e )Statkraft, a Norwegian state-owned electricity company, was the third largest energy producer in the Nordic region in 2007, produced

The official answer is D .
But I could not understand why.. According to the explanation , ' which had 2100 employees.' refers back to Statkarft . but there is no 'AND ' (parallel marker ) before which to refer back to the subject .Please help me if I missed somthing here.

Thanks in advance
anu