6. In government class, Nadia computed the amount of debt of the federal government after a third of it was paid in 1995. The calculator displayed the number 3.28E12. What is this number in scientific notation?
option 1: 3.28 x 10^-12
option 2: 3.28×10^12
option 3: 12 x 10^3.28
option 4: 3.28 x 12 ^10