In plants that have alternation of generations the haploid spores are made by the
a. cotyledon.
b. seed coat.
c. sporophyte.
d. gametophyte.

C. Sporophyte

A sporophyte is a diploid body having two sets of chromosomes. It produces spores through the process of meiosis. These spores are the product of asexual mode of reproduction in plants and the sporophytic phase is the asexual phase in the alteration of generations in plants. The sexual phase is the gametophytic phase. The spores produced are haploid that means they exhibit a single set of chromosomes.  

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.