2021-037

The values of \( \langle k \rangle \) for a network to have a critical threshold \( f_c > 0 \) are:

1. \( \langle k \rangle > 2 \) for any random network and \( \langle k \rangle > 1 \) for any other
2. \( \langle k \rangle > 1 \) for any network
3. \( \langle k \rangle > 2 \) for any network
4. \( \langle k \rangle > 1 \) for any random network and \( \langle k \rangle > 2 \) for any other
5. None of the above

Original idea by: Thales Nazatto