Question 2 5 points Sav How was Pahnal's expansion in Mexico used as a natural experiment for the estimation of the effect of access to savings instruments on outcome variables? The phased expansion was used to construct a comparison group from among the regions where Pahnal expanded in the later phases. Since Pahnal expanded all over Mexico, the non-borrowers formed the comparison group. Pahnal expanded to a set of targeted regions and comparison groups were formed of the regions where they did not expand. Pahnal encouraged savings among individuals with low creditworthiness and the comparison group was formed at the margin of creditworthinessQuestion 1 5 points In the context of a RCT, which of the following problems is specific to individual randomization and does not exist in cluster randomization? O Low take up in the treatment group Attrition Selection bias O Contamination