Read the following article and answer the question by choosing from the options.

They must have a top attainable speed of at least 20 miles per hour but not more than 25 mph . They 're supposed to be able to run 30 miles on one electric charge , which can take six to eight hours . In municipalities that adopt NEV ordinances , NEVs can operate on local streets that have speed limits up to 35 mph . State Department of Transportation approval of the ordinances is needed if municipalities want to allow NEVs to cross state trunk highways - a provision that some object to .

Why does one need to charge their vehicle at night ?
Pick from:
+ The charge takes a long time ..
+ The charging stations are cheaper at night ..
+ None of the above choices ..
+ The charge is nocturnal .....A:
The charge takes a long time .