Among the given options, Bangladesh has more or less evolved a two-party system.

In Bangladesh, the two dominant political parties are the Awami League (AL) and the Bangladesh Nationalist Party (BNP). These two parties have been the major players in the country`s political landscape for several decades, with a history dating back to the pre-independence era of Bangladesh.

1. Awami League (AL): The Awami League is the ruling political party in Bangladesh and has been in power for multiple terms. It was founded in 1949 and played a significant role in the independence movement of Bangladesh. The party has a center-left ideology and has traditionally focused on issues such as secularism, nationalism, and social justice.

2. Bangladesh Nationalist Party (BNP): The Bangladesh Nationalist Party is the main opposition party in Bangladesh. It was founded in 1978 and has a center-right ideology. The BNP has been in power during various periods in the country`s history and has a strong support base, particularly in rural areas.

The two-party dominance in Bangladesh can be attributed to several factors:

a) Historical Legacy: The Awami League and the BNP emerged as prominent political parties during Bangladesh`s struggle for independence. They have since maintained a strong presence in the political arena, building a legacy and establishing themselves as the two major players.

b) Voter Loyalty: Both parties have managed to cultivate strong support bases and loyal voter constituencies over time. The AL has historically enjoyed support from sections of the population advocating for secularism and social reforms, while the BNP has gained support from conservative elements and those favoring a more religiously influenced governance.

c) Alternating Power: Despite occasional political unrest and interruptions in democratic processes, the Awami League and the BNP have taken turns in power, indicating a competitive nature of their rivalry. This alternating power structure has reinforced the idea of a two-party system in Bangladesh.

d) Electoral System: Bangladesh follows a parliamentary system of government, where the majority party or coalition forms the government. This system encourages the formation of broader alliances and strengthens the position of the two dominant parties.

While Sri Lanka, Pakistan, and Myanmar also have multiple political parties, their political landscapes do not exhibit the same level of two-party dominance as Bangladesh. These countries have a broader range of parties and often see coalition governments formed through alliances between multiple parties.

In conclusion, among the given options, Bangladesh has more or less evolved a two-party system, with the Awami League and the Bangladesh Nationalist Party being the dominant political forces in the country.