IP Packet $=$ Data $+$ Header
i.e $4500$ bytes $= 4480$ (Data) $+ 20$ (Header) bytes [Given]
Now MTU is $600$ bytes.
MTU includes Data $+$ Header
$\therefore$ Max data that can be sent is $580$ bytes.
However, the total length should be a multiple of $8$ (except for the last fragment), because this number will be stored in the Fragmentation offset, which specifies the number of bytes ahead of this fragment.
The nearest number to $580$ which is a multiple of $8$ is $576$
Therefore, the fragmentation will be done in this way $\Rightarrow$
$\begin{array}{l|c|c|c|c|c|c|c|c} \hline \text{Fragment#} & 1 & 2 & \textbf{3} & 4 & 5 & 6 & 7 & 8 \\\hline \text{Data(B)} & 576 & 576 & \textbf{576} & 576 & 576 & 576 & 576 & 448 \\\hline \text{Header Length(B)} & 20 & 20 & \textbf{20} & 20 & 20 & 20 & 20 & 20 \\\hline \text{Total Length(B)} & 596 & 596 & \textbf{596} & 596 & 596 & 596 & 596 & 468 \\\hline \text{Fragment Offset(B)} & 0 & 72 & \textbf{144} & 216 & 288 & 360 & 432 & 504 \\\hline \text{More Fragement} & 1 & 1 & \textbf{1} & 1 & 1 & 1 & 1 & 0 \\\hline \end{array}$
Since they have mentioned that the first fragment has an offset of $0$, the third fragment has an offset value of $144.$