We have that scenarios 2, 3, and 4 have the highest likelihood of leading to fixation of an allele based on the combination of selection pressure, migration, and population size.
Model 2:
The Starting frequency: 100% A1, 0% A2.
Then Strong selection pressure for A1A1 genotype (highest fitness).
Has Low mutation rate.
Has No migration or drift.
The Fixation of A1 is highly likely in this scenario because:
Strong selection pressure against A2 favors A1A1 offspring, eliminating A2 over time.
Low mutation rate prevents A2 from re-entering the population significantly.
No migration or drift ensures no external influence on allele frequencies.