What is the meaning of stymied as used in the passage

How would i answer this for an exam?

At which point on the diagram do convection currents occur to drive plate movement?

Select the correct answer. look at this nineteenth-century illustration of london. which explanation best relates this illustration to changes in britain in the 1800s? a. factory workers in cities lost their livelihood because of the lack of housingb. industrialization narrowed the inccome gap between landowners and workers. c.the migration of workers from rural to urban areas resulted in overcrowded citiesd. the spread of railways allowed farmers to sell produce far from where it was grown.