What are the first two characters of an MD5 hashed password?

A.
$1

B.
$5

C.
$6

D.
2a

Explanation:
From the man pages:
$id$salt$encrypted
The following values of id are supported:
ID  | Method
─────────────────────────────────────────────────────────
1    | MD5
2a  | Blowfish (not in mainline glibc; added in some Linux distributions)
5    | SHA-256 (since glibc 2.7)
6    | SHA-512 (since glibc 2.7)