The trait is most likely autosomal dominant. Hence the correct option is e.
The pedigree in Figure 15.3 indicates that the trait is most likely autosomal dominant. This conclusion is drawn from observing the vertical transmission of the trait from one generation to the next, where affected individuals have at least one affected parent.
Autosomal dominant traits typically show a pattern of inheritance where an affected individual has a 50% chance of passing the trait to each offspring. The presence of affected individuals in successive generations without skipping generations is characteristic of autosomal dominant inheritance, supporting the choice of option E. Hence the correct option is e.