premise: In the negotiations over the past two years, it is understandable that table 2 union members had no hesitation using their right to strike, which they had obtained on December 16, 1998. So, in a perfectly legal context, the union is exercising its means of pressure by holding rotating strikes across the country since January 18.
hypothesis: The table 2 union was founded in 1991.
reason: Nothing is mentioned in the text as to when exactly the union was formed, so we don't know. It's difficult because 1998 is mentioned in the text, which probably confused the system.