your answer is D. 32
If it has 5 pairs of chromosomes, it could produce 2^5 or 32 unique chromosomes. The number of different gametes is determined by counting the number of heterozygous chromosomes and raising 2 to this power. So, if all the homologous are exactly the same, there would only be 1 possible type of chromosome.
An organism with NO heterozygous chromosomes, like BB or AAbbCCDDeeFF can produce 2^0 or 1 type of gamete- B or AbCDeF, respectively. An organism with the genotype AaBBccDdee has 2 pairs of hetrerozygous chromosomes (the As and the Ds), so the number of different gametes is 2^2 or 4. So, an organism with 5 pairs of chromosomes, AaBbCcDdEe, could produce 2^5 or 32 gametes: aBCDE, AbCDE, ABcDE, etc.