The correct answer is option 'B' - Challenge of expansion.

Explanation:
The challenge of expansion refers to the task of extending democracy to those sections of society that have historically been excluded from participating in the political process. This challenge is being faced by most democracies around the world today.

1. Historical Exclusion:
- Many democracies were initially established with limited suffrage, excluding certain groups such as women, minorities, and lower-income individuals.
- Over time, there has been a push to expand political participation and ensure equal representation for all citizens.

2. Inclusion of Marginalized Groups:
- Democracies are striving to include marginalized groups in the political process to ensure their voices are heard and their interests are represented.
- This includes efforts to empower women, ethnic minorities, indigenous communities, and economically disadvantaged individuals.

3. Overcoming Barriers:
- The challenge of expansion involves overcoming various barriers to political participation.
- These barriers can be socio-economic, cultural, or institutional in nature.
- Examples include gender-based discrimination, voter suppression, lack of access to education and information, and discrimination against certain ethnic or religious groups.

4. Efforts for Inclusion:
- Democracies are implementing various measures to address the challenge of expansion.
- This includes affirmative action policies, electoral reforms, and efforts to promote gender equality and social inclusion.
- Quotas for women in politics, reservation of seats for marginalized communities, and efforts to increase voter registration and turnout are some of the strategies being employed.

5. Global Significance:
- The challenge of expansion is not limited to specific countries or regions.
- It is a global concern as all democracies strive to ensure equal representation and political inclusion.
- The success of democracy depends on the ability to overcome this challenge and build inclusive societies.

In conclusion, the challenge of expansion is being faced by most democracies around the world as they strive to include historically marginalized groups in the political process. This involves overcoming various barriers and implementing measures to ensure equal representation and political inclusion.