Which type of data structure is illustrated in the C code below?

Hint: You simply need to look at the structure of the code and keywords to determine this answer; you do not need to "know" C$.$

#include

int main$()$

$\{$

int i $=1,$ j;

while $($i $<=5)$

$\{$

j $=1$;

while $($j $<=$ i $)$

$\{$

printf$("\%$d $",$j$)$;

j$++$;

$\}$

printf$("$n$")$;

i$++$;

$\}$

return $0$;

$\}$