Study the following class definition:

class Athlete

$\{$

public:

Athlete$($double new$\_$speed$)$;

void train$()$;

void run$($double new$\_$speed$)$;

void rest$()$;

double get$\_$speed$()$ const;

private:

double speed;

$\}$;

Which of the following options would be legal in the definition of the void run$($double new$\_$speed$)$function$?$

Question $13$ options:

this$->$speed $=$ this$->$new$\_$speed;

speed $=$ this$->$new$\_$speed;

this$->$speed $=$ new$\_$speed;

this.speed $=$ new$\_$speed;