Which convention does German Renaissance artist Matthias Grünewald use in the Isenheim altarpiece? A. The altarpiece incorporates the medieval belief that art should communicate a religious idea.
B. The figures on the altarpiece have idealized proportion and facial expressions.
C. The artist followed the Italian Renaissance convention of using one-point perspective to create a sense of depth.
D. The altarpiece incorporates the Italian Renaissance ideal that art should communicate intellectual ideas.

Isenheim Altarpiece, painting by Matthias Grunewald, showing Crucifixion at the center, Saint Sebastian and Saint Anthony on its wings and Lamentation of Christ on the stand

A. The altarpiece incorporates the medieval belief that art should communicate a religious idea.

Explanation:

Chruch and religion had dominance over all the aspects of life during medieval times. Many people were uneducated and illiterate and only education and art were in the domain of the church. Therefore, the art was supposed to be mostly religious and depict the scenes from the Bible and the life of Jesus.

The altarpiece depicts religious themes, most notably the image of crucifixion in the middle. The scene of spiritual presence, suffering, Christ’s temptations, and passionate parts of the Bible were commonly depicted during the Middle ages, so the huge and detailed, almost grotesque, altarpiece is the perfect example of the art that follows those traditions.

the answer is b. i'm positive it's that answer.