Final answer:
The activity frequently found in German labor relations is option d, which describes collective bargaining over wages and conditions of employment occurring formally outside the individual plants.
Step-by-step explanation:
The activity frequently found in the labor relations of Germany that best suits the description provided is d. Collective bargaining over wages and conditions of employment (job classification, working time, and working conditions) occurs formally outside the plant. In Germany, labor unions and employer associations typically engage in industry-wide negotiations that determine standards for wages and working conditions. This collective bargaining process is sectoral rather than localized and is a key feature of the German model of industrial relations.
In contrast, single system industrial relations, low levels of unionization, especially in the engineering industries, and union organization at a localized level only are not characteristic of the German model. Arbitration at the individual plant level on wages also does not usually characterize German labor relations, as negotiations and arbitration often happen at the industry level.
Germany's system tends to involve comprehensive coverage, where even non-union members frequently benefit from the collective bargaining agreements negotiated by the unions. This is a contrast to some other countries, including the United States, where union coverage and membership tend to be more aligned, and where industry-wide collective bargaining is less prevalent.