Option 1 (It describes the days being discussed) is correct since it refers to a particular set of days, those in which the subject of the sentence goes jogging, and a particular moment of the day which is the morning.
Option 3 (It creates a compound-complex sentence) is correct because the sentence contains two independent clauses and a dependent clause.
The two independent clauses are: "<em>My mind seems to process ideas faster</em>" and "<em>My mood is more positive</em>". These two independent clauses are joined by the coordinating conjunction "<em>and</em>". The compound-complex sentence also includes a dependent clause "<em>On days when I go jogging in the morning</em>" which is dependent on the two main independent clauses previously mentioned.
