Final answer:
Phoning your elected official cannot be considered a group-level form of political participation as it is a personal action, unlike being part of a political party, protesting, or working for a political campaign which involve collective action.
Step-by-step explanation:
Group-level forms of political participation involve collective actions and efforts that aim to influence political processes or policy outcomes. Among the options given, the act that cannot be considered a group-level form of participation is c. Phoning your elected official.
This is because phoning an elected official is typically a personal act that one does individually, rather than as part of a group or collective effort.
On the other hand, being part of a political party, taking part in a protest, and working for a political campaign are all activities that involve collective action and therefore can be considered group-level forms of political participation.