Answer:
The doctor notified the patient <em><u>that</u></em><u> he had only six months left.</u>
Explanation:
The subordinate clause is a dependant clause. Essential, it cannot stand by itself. After reading both clauses, we realize the first clause can stand alone.
<em>The doctor notified the patient</em>
Thus, it must be the second clause.
The conjuction conncects both clauses. The word <em>that</em> connects the two cluases.