Molecular Cloning Questions

I was just hoping someone might answer these questions for me. I'd really appreciate it.

GEL EXTRACTION OF VECTOR
(following digestion of vector by 2 restriction enzymes and dephosphorylation using CIP)

Which of these statements is false?
a) gel purification is the only way to separate non-digested from digested vectors
b) gel purification separates single-digested from double-digested vectors and can replace the need for dephosphorylation
c) dephosphorylation is the only way to combat against the ligation of single-digested vectors in a ligation reaction
d) CIP (calf intestine phosphatase) cannot be degraded easily and gel purification helps separate the DNA from CIP.

LIGATION OF VECTOR AND INSERT

Which condition is not required in the ligation reaction?
a) vector only
b) vector + insert
c) vector + T4 ligase
d) vector + insert + T4 ligase

COLONY SCREENING

A textbook result of the transformation is as follows
a) vector (2 cfu), vector + T4 ligase (5 cfu), vector + insert + T4 ligase (50 cfu)
b) vector (50 cfu), vector + T4 ligase (5 cfu), vector + insert + T4 ligase (5 cfu)
c) vector (1 cfu), vector + T4 ligase (5 cfu), vector + insert + T4 ligase (5 cfu)
d) vector (5 cfu), vector + T4 ligase (50 cfu), vector + insert + T4 ligase (50 cfu)