A Uniform Magnetic Field Is Directed into the Page

Multiple Choice

A uniform magnetic field is directed into the page. A charged particle, moving in the plane of the page, follows a clockwise spiral of decreasing radius as shown. A reasonable explanation is:

A) the charge is positive and slowing down
B) the charge is negative and slowing down
C) the charge is positive and speeding up
D) the charge is negative and speeding up
E) none of the above