Final answer:
In medieval music, the plucked instruments with open strings and fixed tunings are the lute and the harp, which played essential roles in shaping the era's musical soundscape.
Step-by-step explanation:
The medieval plucked instruments with "Open" strings and fixed tunings include the lute and the harp. Unlike the violin, which uses a bow to produce sound, and the clarinet, which is a reed instrument, both lutes and harps have strings that are plucked to create music. These instruments were essential in the performance of medieval music, contributing significantly to the soundscape of the era. The lute was a popular instrument and came in various forms like the mandore and gittern. The harp, with its open strings, played a vital role in medieval music compositions.