In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: In what country was Folkersam during the Battle of the Bulge? Passage:In 1944 Folkersam's unit transferred to the Waffen-SS and became the major part of SS-Jagdverband Ost. This unit was active on the Eastern Front and took part in the kidnapping of Miklos Horthy, Jr. and the deposition of his father, the Hungarian regent Miklos Horthy in Operation Panzerfaust. During the Battle of the Bulge, Folkersam participated in Operation Greif, and worked in close coordination with Otto Skorzeny. In January 1945, having posted to the Eastern Front, he fought against the advancing Red Army in central Poland. Adrian von Folkersam was killed in action on 21 January 1945 near Inowrocaw, Poland. At the time of his death, he was an SS-Hauptsturmfuhrer (captain), and was in command of the SS-Jagdverband Ost.
Links: a. Battle of the Bulge b. Otto Skorzeny c. Red Army d. Operation Greif
d