The correct option is A
Three pairs thoracic and six pairs abdominal
In cockroach, the sub-oesophageal ganglion arises a double nerve cord which travels through the thorax and abdomen below the alimentary canal on the ventral side up to the posterior end of the body. The nerve-cord has three large ganglia in the thorax, one each for pro-, meso-and metathoracic segments, therefore, they are called prothoracic, mesothoracic and metathoracic ganglia.
The nerve cord has six ganglia in the abdomen which lie in the 1st, 2nd, 3rd, 4th, 5th, and 7th segments. In Cockroach nerve cord ganglia are three pairs of thoracic and six pairs of abdominal.
So the correct answer is 'Three pairs thoracic and six pairs abdominal'.