Which shells will run the following code without error$($s$)?$ That is$,$ which shells use the following syntax

for if statements.

a$=2$

if $[$ $a $-$lt $4]$

then

echo test is true

else

echo test is false

fi

a$.$ All shells in the Ubuntu family of distributions.

b$.$ All shells in the Debian family of distributions.

c$.$ Shells of the sh and bash family.

d$.$ Shells of the csh and tcsh family.

e$.$ All of the above

f$.$ None of the above