What is a potential risk of instability in one Eurozone country?

In the context of the Eurozone, a potential risk of instability in one country is that this instability can spread to other countries in the region. This phenomenon occurs because economies within the Eurozone are interconnected; financial troubles in one nation can lead to increased investor anxiety, affecting confidence in neighboring economies. For instance, if one country faces a severe economic crisis, it may lead to higher borrowing costs not just for itself but also for its neighboring countries, as investors may perceive them as risky investments too. This contagion can manifest in various forms, including market volatility, decreased investment, and lower economic growth across the region, further exacerbating the initial country's difficulties.

The other options suggest positive outcomes, which are less likely in the face of instability. Neighbors may not experience economic growth, currency values may decline due to increased instability, and trade relations generally suffer in times of economic turmoil. Thus, the risk of instability spreading underscores the system's interdependence within the Eurozone.