please help

Select all of the following that are correct definitions for f' (a). lim f(x) - f(a) - a Of (x) - f(a) a - a O lim f(ac) - f(a) ac - a Of(ath) - f(a) h lim flat h) - f(a) h-0 h O lim flat h) -f(a) hWhich of the following represents f (1) if f (x ) = ? x+1 O 1 0 - 1 O 1 lim x+1 x-1 x - 1 O 1 +1 - 1 lim x-+1 x - 1 O lim x-1x+1