These statements are typed in the Python shell:

$>a=4$

$>b=a$

$a\frac{?}{?}$# Statement $3$

$b\frac{?}{?}$# Statement $4$

$>b=3$

$a\frac{?}{?}$# Statement $6$

$b\frac{?}{?}$# Statement $7$

If $4$ and $4$ are displayed when statements $3$ and $4$ are executed, what numbers are displayed when statements $6$ and $7$ are executed?

$4$ and $4$

$3$ and $4$

$4$ and $3$

$3$ and $3$