To determine the joint relative frequency of adults who prefer Android from a two-way relative frequency table, you would typically need to refer to the specific values presented in that table.
However, since the options you provided are percentages (18%, 32%, 22%, and 28%), the answer would generally be the percentage that represents the count of adults who prefer Android compared to the total population represented in the table.
If we assume that each percentage represents the joint relative frequency for a particular preference, the joint relative frequency of adults who prefer Android would be the number corresponding to Android preferences.
Without the actual data from the two-way table, choosing the correct option is not possible. If there was a specific value from the table that indicated the joint relative frequency for Android, that would be the answer. Thus, you would need to provide additional information from the table for an accurate determination.