4. Workers digging a tunnel for an underground railway complete 5 metres of tunnel on a typical day. Working every day, how long will it take them to dig a tunnel of length 2 kilometres?
A three months
B six months
$\mathrm{C}$ just under a year
D just over a year
E nearly two years
4. D The number of days required to dig the tunnel is $\frac{2000}{5}=400$. This is just over one year.