This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Black Triangles' act as a source of plaque accumulation and flossing interference, this should be treated by: 
Select and explain. 
A. Fill the entire embrasure space with pink porcelain, B. Andrew's bridge system can be given, C. Large pontics can be given, D. Both 1 & 2
D: Both 1 & 2
Answer: D: Both 1 & 2 
Explanation: Black Triangles’ can be treated by:

Filling the entire embrasure space with pink porcelain.
Andrew's bridge system
Increasing the connector height

Loss of residual ridge contour may lead to unesthetic open gingival embrasures (“black triangles”), food impaction and percolation of saliva during speech.