Please finish the following MATLAB function that takes a character vector $($str$)$ as the input and count the occurrence of the existing substring $($word$).$ E$.$g$.$ the call to the function

Count$(\text{'}$This is a test.$\text{'},$ 'test'$)$

will return $1.$

Function strfind$($TEXT$,$PATTERN$)$ returns the starting indices of any occurrences of PATTERN in TEXT.

function n$=$Count$($str$,$ word$)$

b$=$strfind$($str$,$word$)$;

$\_\_\_\_\_\_\_\_\_$

Question $5$ options:

A$)$

if ~isempty$($b$)$

n$=$size$($b$)$;

else

n$=0$;

end

B$)$

if isempty$($b$)$

n$=$size$($b$)$;

else

n$=0$;

end

C$)$

if ~isempty$($b$)$

n$=$length$($b$)$;

else

n$=0$;

end

D$)$

if isempty$($b$)$

n$=$length$($b$)$;

else

n$=0$;

end