What was the reason Qatar had faced almost 3 years of diplomatic cut-offs from the rest of the Gulf Countries?

What was the reason Qatar had faced almost 3 years of diplomatic cut-offs from the rest of the Gulf Countries?A. It supported the US against Iraq
B. Qatar was accused of supporting terrorist groups and being close to Iran
C. Qatar had restricted the use of its massive airbase Al- Udeud
D. None of these