Regarding Ewings sarcoma (Choose a single answer):
a) Ewings sarcoma is typically a tumor of middle-age and beyond.
b) Tubular bones are most commonly affected in Ewings sarcoma in patients under 20 years old, with flat bones most commonly affected in those older than 20.
c) In Ewings sarcoma, bone metastases are uncommon and unlike the primary tumor, are usually blastic when they do occur.
d) The vast majority of occurrences of Ewings sarcoma in the long bones are of the central diaphyseal type.