"Er is sterke concurrentie tussen de bedrijven."
Translation:There is strong competition between the companies.
Probably a missing alternative translation. You can help the course builders by reporting errors and missing alternative translations using the report a problem button during lessons. They need input from users like you to improve the course!
So, how would you say "stiff competition" in Dutch? I felt "strong competition" sounded awkward in English to describe a competition in which the competitors are formidable (strong).
Stiff competition = stevige concurrentie.
But the regular expression in Dutch is "sterke concurrentie"
'sterke mededinging' would work; mededingen is the infinite form, which is not what you want in that sentence -- it would translate approximately to 'there is strong to compete between the companies', which is obviously incorrect.
Having said that, 'mededinging' is not very common; I had to think twice to understand what you meant. Concurrentie is much clearer in this context.