Out of following which ganglia unite to from nervering in nervous system of Cockroach ?
(A) Suboesophageal, supraesophegeal and circum oesophageal commisures unite to form nervering.
(B) Three ganglia in thorax region and six ganglia of abdominal region unite to form nervering.
(C) Three pairs of ganglia in thorax region and six pairs in abdominal regions.
(D) Three pairs supraoesophageal and one pair suboesophageal ganglia unit to form nervering.
