The most common and most likely answer to this crossword clue is the 4 plus 3 plus 6 letter word PICK AND CHOOSE
P
I
C
K
A
N
D
C
H
O
O
S
E
Buddy explains!
The straight part
We know that "Carefully select" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case carefully select = pick and choose.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.