What is$/$are some issue$($s$)$ with abstract data types?

$1)$

Difficult to reuse

$2)$

Lack of organization due to being at the same level

$3)$

None, they solve most of the issues with primitive data types

$4)$

Both a$)$ and c$)$

$5)$

Both a$)$ and b$)$

$6)$

Both b$)$ and c$)$

$7)$

None of the above