Now that we've updated Course to "remember" how many sections it has, we can start to implement a Section class.$$ Every Section has a sectionId $($String$)$ and an instance of Course.$$ For example, we might have a Course with title "ITP$120"$ and description$$ "Java", and there might be three sections of that Course.$$ For our first version, each Section will have an attribute that stores$$ its Course instance.$$ With this structure, a Section "knows" its Course, but a Course does not "know" its sections.$$ Which of these Section implementations is most correct?

Group of answer choices

public class Section $\{$

$$public String sectionId;

$$public String course;

$\}$

public class Section $\{$

$$public String sectionId;

$$public Course course;

$\}$

public class Section $\{$

$$public Section sectionId;

$$public String course;

$\}$