Answer
The picture is attached below.
The hydrogen shown in purple are primary.
The hydrogen shown in black are secondary.
Work Step by Step
Starting from right-hand side, the first carbon has 3 hydrogen atoms. These hydrogen atoms are bonded to a carbon that is bonded to one R group. These hydrogen atoms are therefore primary.
The second carbon has 2 hydrogen atoms. These hydrogen atoms are bonded to a carbon that is bonded to 2 R groups, these hydrogen atoms are therefore secondary.
The next carbon also has 2 hydrogen atoms. These hydrogen atoms are bonded to a carbon that is bonded to 2 R groups, these hydrogen atoms are also secondary.
The fourth carbon has 3 hydrogen atoms. These hydrogen atoms are bonded to a carbon which is bonded to 1 R group, these are therefore primary hydrogen.
