Homozygous, phenotypes!?

Question

Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether cactuses have spines. Homozygous recessive nn cactuses have no spines at all.

A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce
A) all sharp-spined progeny.
B) 50% sharp-spined, 50% dull-spined progeny.
C) 25% sharp-spined, 50% dull-spined, 25% spineless progeny
D) all spineless progeny
E) It is impossible to determine the phenotypes of the progeny.

Answer 1

I think the answer is "A", but you could not determine the outcome for the F2 generation without more information. The cross would be SSNN x ??nn (the ? could be S or s)

Answer 2

Parents would be SSNN x ??nn
Offspring are S?Nn = all sharp-spined.

Answer is A, even if we don't know if the second parent is SS, Ss, or ss. It doesn't matter.

Answer 3

All sharp spined cacti (they would all carry the recessive trait for no spines--so if bred to each other - here is where you would get the possiblity for spineless cacti.