$2.$ What are the stable outputs of an S$-$R flip$-$flop?

$3.$ A counter is generally built with. Choose:

a$.$ Latches

b$.$ Positive edge$-$triggered latches

c$.$ Negative edge$-$triggered latches

d$.$ Flip$-$flops

e$.$ Positive edge$-$triggered flip$-$flops

f$.$ Negative edge$-$triggered flip$-$flops