The second option: meiosis and fertilization
process A is meiosis, you can see that the gamete(haploid cell) results from the diploid cell. The gamete has n chromosomes(39), whereas the diploid cell has 2n(78)
process B is fertilization the two gametes(haploid) fuse together to form the zygote(diploid)
B, proton is positive and it does not represent the symbol
C hope that helps have a good one