\textbf{165.} A 1 kg object is released in vacuum conditions and reaches the ground after 4 seconds. The work done by gravity in the third second of fall is how many Joules? ($g = 10\,\frac{m}{s^2}$)
\hspace{1cm} (1) $150$ \hspace{2cm} (2) $250$ \hspace{2cm} (3) $400$ \hspace{2cm} (4) $450$