Starting with the Punnet square, the yellow would have the genotype YY and the goober would have the genotype YB, so the cross YY x YB would be as follows:
a) As we can see, the offspring would be 50% YB and 50% YY.
b) 50% (half) of the offspring would be yellow (YY)
c) 0% (none) of the offspring would be blue (BB)
d) 50% (half) of the offspring would be goobers (YB)