The Fact That Neurons Fold in on Themselves and Collapse

The fact that neurons fold in on themselves and collapse due to the destruction of microtubules has been implicated in Alzheimer's disease.Which of the following is not a function of microtubules?

A) anterograde transport,or the transport of organelles to the end of the axon
B) production of ribosomes
C) helping to maintain the shape of the cell along with the neurofilaments
D) retrograde transport or transport of organelles back to the cell body