题目选项分析

Just as Edward Jenner used the pustules from milkmaids to inoculate against smallpox, effectively removing the specter of death that had hung over the population, so immunologists today use the pustules of infected organisms to obtain a live virus from which the modern smallpox vaccine is derived

Just as Edward Jenner used the pustules from milkmaids to inoculate against smallpox, effectively removing the specter of death that had hung over the population, so too do today's immunologists in deriving the smallpox vaccine of a live virus, which has been obtained from the pustules of infected organisms