How do regional alliances influence relationships between countries and with other alliances?

  The regional alliances tend to have very positive effect on the relationship between the countries that are in the alliance. The reason for that is that in the regional alliances the countries are helping and supporting each other in multiple ways, with the prime goal being that all of them have a benefit from it. Usually, the prime collaboration and support is economic, but it also stretches into political and cultural level, as well as collaboration and support in the safety of the countries.

  The regional alliances may have good or bad relations with other alliances, depending on the situation, do they have similar interests or are rivals, so we have lot of regional alliances that have great relationship with other alliances, but also some that are in bad relations with the others.

a and b because with the other three, they simplify to something else.