Suppose you are a researcher in an influenza lab and your team has uncovered four strains that have evolved changes from last year’s influenza virus. strain a has evolved four changes in its surface proteins and three changes in its interior proteins. strain b has evolved two changes in its surface proteins and seven changes in its interior proteins. strain c has evolved six changes in its surface proteins and none in its interior proteins. strain d has evolved only a single change in its surface proteins and none in its interior proteins. assuming that all other factors are equal, which strain is most likely to be infectious?