How many carbon atoms are present in the longest parent chain of the given structure?

(9) To determine the longest parent chain,we identify the continuous chain of carbon atoms with the maximum number of atoms.
Looking at the structure:
$CH_3-CH(CH_3)-CH_2-CH_2-CH_2-CH(CH_2-CH_2-CH_3)-CH_2-CH_3$
If we follow the path labeled as $B$ in the image,the chain consists of $9$ carbon atoms.
Therefore,the longest parent chain contains $9$ carbon atoms.