A coil experiences the following variation of magnetic flux with time:
• 0≤t<2s: flux increases steadily.
• 2≤t<4s: flux is constant.
• 4≤t≤6s: flux decreases at a faster rate than the first interval.
Which sequence gives the sign of the induced emf in these three intervals respectively?
a) Positive, Zero, Negative
b) Negative, Zero, Negative
c) Negative, Zero, Positive
d) Zero, Zero, Positive