$(12$ marks$)$ The data sg$\_$subzones $.$rds contains an sf object of $310$ subzones of Singapore,

with the population values for these zones. The data is already outdated and contains

errors and missing values, which we will not do anything about.

$($a$)(3$ marks$)$ Find the EPSG value of this sf object. Convert it to another sf object and

name it $"$sg$.$subzones$1"$ with the EPSG value of $4326.$

$($b$)(6$ marks$)$ Following $($a$),$ remove all those subzones with NA population values, and

name the sf object $"$sg$.$subzones$2".$ Add a new variable log$\_$total to sg$.$ subzones$2$

which is computed from $lo{g}_{10}($population $+1).$ Here $+1$ is to avoid taking logarithm

of zeros. Use ggplot $()$ to plot all the remaining subzones and fill in the color using

the variable log$\_$total.

$($c$)(3$ marks$)$ Identify the top $5$ most populated regions.