During the mid 19th century Industrial Revolution, the average life span of workers in Manchester was 17 years. This option suggests that the average lifespan of workers during this period was quite short. There are several factors that contributed to this low life expectancy. Firstly, the working conditions in factories and mines were extremely hazardous and dangerous. Workers were often exposed to harmful substances, such as coal dust and toxic fumes, which led to respiratory diseases and other health issues. Secondly, many workers lived in overcrowded and unsanitary living conditions, which increased the spread of diseases like tuberculosis and cholera. Additionally, malnutrition and poor access to healthcare were common problems among the working class, further reducing life expectancy.

It is important to note that this answer provides a generalization and may not accurately reflect the life span of every worker in Manchester during this time period. It represents the average life span, taking into account the significant number of workers who died at a young age due to the harsh working and living conditions.