"<span>(c)the ability of citizens to vote" is the best answer but this is very misleading. A referendum is when the citizens vote directly on a specific issue of policy. It's not their ability to vote for mayors, legislators, etc.</span>
Answer: make changes in (something, typically a social, political, or economic institution or practice) in order to improve it.
Explanation: Reform means the improvement or amendment of what is wrong, corrupt, unsatisfactory, etc. The use of the word in this way emerges in the late 18th century and is believed to originate from Christopher Wyvill's Association movement which identified “Parliamentary Reform” as its primary aim.
No because it was a dangerous expedition