The correct answer is: All of the above.
Lack of agricultural land is a major factor contributing to out-migration from rural areas of Assam. The state has a high population density, and the amount of land available for agriculture is limited. This has led to a situation where many farmers are unable to make a living from their land, and are forced to migrate to urban areas in search of employment.
Frequent flooding is another major factor contributing to out-migration from rural areas of Assam. The state is located in a flood-prone region, and many villages are regularly inundated by floodwaters. This can damage crops, homes, and infrastructure, and make it difficult for people to live in these areas.
Limited employment options are also a major factor contributing to out-migration from rural areas of Assam. The state has a high rate of unemployment, and there are few opportunities for people to find well-paying jobs in rural areas. This has led to a situation where many people are forced to migrate to urban areas in search of employment.
In conclusion, all of the factors mentioned in the question contribute to out-migration from rural areas of Assam. These factors have led to a situation where many people are forced to leave their homes and communities in search of a better life.