An adjustable rate mortgage with a teaser start rate of 1.5%, an index of six month LIBOR,

Question:

An adjustable rate mortgage with a teaser start rate of 1.5%, an index of six month LIBOR, a margin of 2.0%, and periodic and lifetime caps of 2/6 with semi-annual adjustments, would have a maximum interest rate of what at the beginning of the fourth loan year if six month LIBOR is 4.5% at that time?
a) 5.5%
b) 6.5%
c) 7.5%
d) 85%