Answer:
Belinda can expect to make $1 more with option B.
Explanation:
The expected value for every option is calculated as:

Where
and
are the posibles money prize and
and
are their respective probabilities.
Option A:
Belinda has 12 possibilities: 1-3, 1-4, 1-5, 3-1, 3-4, 3-5, 4-1, 4-3, 4-5, 5-1, 5-3 and 5-4
From that 12 possibilities, there are 6 that have a sum greater than 6. That possibilities are: 3-4, 3-5, 4-3, 4-5, 5-3 and 5-4
So, the probability that the sum of the two spins is greater than 6 is:

At the same way the probability that the sum of the two spins is lower or equal than 6 is 0.5.
So, the expected value for this option is:

Option B:
Belinda has 8 possibilities: HHH, HHT, HTH, HTT, THH, THT, TTH and TTT
Where T means Tails and H means Heads.
Form that 8 possibilities, there are 4 which heads appear twice. That possibilities are: HHH, HHT, HTH and THH.
So, the probability that head appear twice is:

At the same way, the probability that head doesn't appear or appear once is equal to 0.5
So, the expected value for this option is:

Finally, Belinda can expect to make $1 more with option B.
