Which of the following statements are true concerning wedges?
                  1. A physical wedge is made of dense material (usually steel) and fits into the head of the gantry
                  2. A dynamic wedge has only one angle size
                  3. A universal wedge has no wedge angle at all
                  4. A dynamic wedge has no wedge angle at all
                  5. More dose is attenuated through the heel of the wedge than the toe

a) 1, 2, 4, 5
b) 1, 5
c) 2, 3
d) 1, 4
e) All of the above