D. "Ebola’s ability to devastate populations is a result of…" is the correct choice because it directly connects the specific story of Emile and his family to the broader impact of Ebola on communities. This transition sets the stage to discuss how the virus spreads and its widespread consequences.
Furthermore, this transition allows for a seamless shift from discussing a single case to the wider implications of the outbreak, highlighting the severity and urgency of public health responses to Ebola.