Final answer:
The correct answer is option a) With Ottoman support.
Step-by-step explanation:
Vlad II Dracul returned to Wallachia in the winter/early spring of 1444 with Ottoman support. This period was marked by complex power dynamics in Eastern Europe, with Wallachia positioned between the conflicting interests of the Ottoman Empire and other European powers. Following the death of Murad II, Vlad sought to reclaim the throne against his rivals and thus secured Ottoman backing to achieve this.
His return was not as a conquering hero, but with the calculated support of a formidable ally in the region. This affiliation was delicate and would impact the political landscape of Wallachia and its relations with surrounding powers, including the Byzantine Empire which was under siege by the Ottomans during this period.