New Delhi, June 30 (ANI): West Bengal Governor MK Narayanan on Monday resigned from his post amidst pressure on UPA appointed governors by the NDA government to step down. His resignation comes in the series of resignations of Governors who were appointed by the UPA government and have now been asked by the Narendra Modi government to quit on the grounds that 'they were not appointed on credit'. Earlier, the Central Bureau of Investigation had questioned Narayanan in the AgustaWestland chopper scam probe. MK Narayanan was the National Security Advisor at time of the chopper deal.