If the stated purpose was to display trends within the Flores del Mundo’s total membership data then I would choose a line graph without dots in an effort to solely highlight the general trend.
If the total membership data split into employee, spouse, and child was being shown I would use a cluster column bar graph. This sort of graph would allow for the viewer to see the comparisons over time between the 3 subgroups while also seeing the general trend of membership data over the year. This sort of graph can become cluttered so significant time would be spent with color and labels in an effort to make the chart simplistic and intuitive.
If Northern and Eastern were being displayed on the same charts tracking membership trends over the year I would resort back to the line graph without dots in 2 different colors.