Solve the equation: 2a4+1=7a2
a. {−7 + 4√−2i, −7 - 4√−2i, 7 - 4√−2i, 7 + 4√−2i}
b. {7 - 4√4, 7 + 4√4}
c. {−7 - 4√4, −7 + 4√4}
d. {−7 + 4√−2, −7 - 4√−2, 7 - 4√−2, 7 + 4√−2}