If I were to guess, I think B is the correct answer. The Nepalese people are hoping that the Maoists will do something "different". They don't have to be excellent, just something "different" than the usual crap delivered by the UML and NC will make the people happy. The second reason why they are voting for Maoists is not mentioned in your choices.

Nepalese people came to the streets the last time to kick the monarchy system out into non-existence. But, the UML and NC politicians were adamant about trying to save the monarchy and install a ceremonial monarchy system, just like in the UK. What they did not realize was how much this pissed off most of the voters who risked their lives demonstrating in the streets the last time in order to get rid of the monarchy in Nepal.

I am not saying that everyone wants to get rid of the monarchy; I'm just saying that the "majority" (greater than 50%) of the people do. And, the results of this election shows that opinion loud and clear. People are voting for the Maoists not because they are the best, but because they have promised to deliver us a Federal Republic without monarchy if they win. And, the way the results are coming out, it looks like the Nepali population believes that the Maoists will keep their promise.

Also, the people were sick of the previous politicians. Just look at the list of people who lost. Most of those old politicians were either too conservative or too corrupt. They had been elected 3 or 4 times before, and have never delivered in their promises. Madhav Nepal, Sushil Koirala, Khum Bahadur Khadka, etc. have lost because they have always taken their voters for granted. They have been elected 3 or 4 times before, but they have never performed. So, I guess, people decided to give the newcomers a chance to prove if they can actually do some good for the country and the people.

I don't know if there is any other explanation