What does the following code snippet print?

$```$python

class C:

a $=4$

def $\_\_$init$\_\_($self$,$ a$)$:

self.a $=$ a

x $=$ C$(1)$

x$.\_\_$init$\_\_(3)$

C$.$a $=2$

print$([$C$.$a$,$ x$.$a$])$

$```$

$-[$x$]`[2,1]`$

$-[]`[4,3]`$

$-[]`[2,3]`$

$-[]`[4,1]`$