The correct answer is: Both a and c.
Traditional irrigation systems in Arunachal Pradesh include bamboo drip irrigation and diversion channels.
Bamboo drip irrigation is a traditional method of irrigation that uses bamboo pipes to drip water directly onto the roots of plants. This method is very efficient in water usage and can be used in areas where there is limited water availability.
Diversion channels are artificial channels that are used to divert water from rivers or streams to agricultural fields. This method is more efficient than bamboo drip irrigation in terms of water usage, but it requires more infrastructure to build and maintain.
Both bamboo drip irrigation and diversion channels are effective methods of irrigation that are used in Arunachal Pradesh. The choice of which method to use depends on the specific needs of the farmer and the availability of water.