For the class Employee example provided in tutorial $3\mathrm{.}1\mathrm{.}7,$ what code segment could be added to keep track of the number of job titles ever held by an employee in a variable called numJobTitles?

public String setJobtitle$($String title$)\{$

if $($title$.$length$()>0)\{$

this.jobtitle $=$ title;

this.numJobTitles $+=1$;

$\}$

$\}$

public int getNumJobtitles$()\{$

return this.numJobTitles;

$\}$

public void setJobtitle$($title$)\{$

if $($title$.$length$()>0)\{$

this.jobtitle $=$ title;

this.numJobTitles $+=1$;

$\}$

$\}$

public int getNumJobtitles$($numJobTitles$)\{$

return this.numJobTitles;

$\}$

public void setJobtitle$($String title$)\{$

if $($title$.$length$()>0)\{$

this.jobtitle $=$ title;

this.numJobTitles $+=1$;

$\}$

$\}$

public void getNumJobtitles$()\{$

return this.numJobTitles;

$\}$

public void setJobtitle$($String title$)\{$

if $($title$.$length$()>0)\{$

this.jobtitle $=$ title;

this.numJobTitles $+=1$;

$\}$

$\}$

public int getNumJobtitles$()\{$

return this.numJobTitles;

$\}$