Why Are Vasoconstrictors Important Additives to the Local Anesthetic Solution

Why are vasoconstrictors important additives to the local anesthetic solution?
1) They provides hemostasis at the injection site.
2) They reduces the possibility of systemic toxicity.
3) They prolongs the duration of the anesthetic's effect.
4) They increases the blood flow to the area.

A) Some other combination
B) 2, 3
C) 1, 2, 3
D) All of the above