How can I represent the entity types depicted in an ERD as relations with attribute names?
Considering the Course entity type that you describe, I have made the following assumptions:


A Course is primarily identified by its CourseNumber
A Course is alternately identified by its Name
A Course is registered at a CreatedDateTime


So I reformulated the situation as follows:


A Course is the dependent in zero-one-or-many CourseDependences
A Course is the determinant in zero-one-or-many CourseDependences


Then, I supposed that:


A CourseDependence is primarily identified by its DependentCourseNumber and DeterminantCourseNumber
A CourseDependence is registered at a CreatedDateTime


This means, yes, that there is a conceptual-level many-to-many (M:N) association (or relationship) that may involve distinct instances of the entity type called Course. Such an association implies the existence of an associative entity type that, as noted, I denominated CourseDependence.

Consequently, from the set of formulations described above, I have derived the IDEF1X1 diagram shown in Figure 1:



In this way, employing the notation that you use to express relations along with their corresponding attribute names, I would represent (a) the Course entity type and (b) the CourseDependence associative entity type as two distinct relations in the following way:


Course = (CourseNumber, Name, CreatedDateTime)
CourseDependence = (DependentCourseNumber, DeterminantCourseNumber, CreatedDateTime)


Therefore, the Option 3 exposed in your question would be very close to an accurate possibility to express the relevant aspects.



Endnote

1. Integration Definition for Information Modeling (IDEF1X) is a highly recommendable data modeling technique that was established as a standard in December 1993 by the United States National Institute of Standards and Technology (NIST). It is solidly based on (a) the early theoretical work authored by the sole originator of the Relational Model, i.e., Dr. E. F. Codd; on (b) the Entity-Relationship view, developed by Dr. P. P. Chen; and also on (c) the Logical Database Design Technique, created by Robert G. Brown.