In general, for most things, A would be correct (Any time of the day). It kind of depends on what you ar collecting the sample for. I think the earlier the better but it doesnt usually matter.
That seems like something you would need to call the business you are seeking an appointment with on a daily basis, to find out if they've had any cancellations. Some businesses have ways to set appointments online, but not all of them do.
The Genotypes would have to be dominant too, but that means multiple options unless you can clarify more but the options would be: Cc, Cc or CC,CC or CC Cc.
C because if a storm drain overflows the drain will start to leak storm water