B  

Partial veneer (three-quarter) crowns depend on a tall axial wall to obtain the frictional retention that is lost when the facial surface is left un-covered. When the clinical crown is short, this vertical height is insufficient, so the restoration cannot be retained or resist dislodging forces; therefore short teeth are a contraindication. Experimental work has shown that partial-veneer preparations have markedly lower retention, which becomes critical when crown height is reduced [Potts et al., 1980, PMID 6986461].