Final answer:
Without additional context or genetic information, it is not possible to determine the genotype of animal III-3 STR B. The options provided represent alleles of different lengths in base pairs, but more data is required to accurately identify homozygous or heterozygous alleles for this specific genetic marker.
Step-by-step explanation:
The student's question about the genotype for animal III-3 STR B cannot be answered accurately without additional genetic information or pedigree data. To determine the specific genotype, one would require more context, typically provided in the form of a family tree or genetic data chart that illustrates how the short tandem repeat (STR) patterns are inherited in the given animal population.
The options in the answer choices (a, b, c, d) appear to represent alleles of different lengths in base pairs (bp). The genotype represents the pair of alleles inherited from the parents for a specific genetic marker. In the context of STRs, each allele is characterized by a certain number of repeating units, which translate into lengths measured in base pairs.
Without specific pedigree or genetic information, it is impossible to conclude whether animal III-3 has homozygous (same length alleles, e.g., 300bp/300bp or 250bp/250bp) or heterozygous (different length alleles, e.g., 250bp/300bp) alleles for STR B. Additionally, the provided reference information (a-d) about genotypes and phenotypes cannot be directly applied to this question as it stands by itself without any connection to the animal's genetic context.