In the String Theory That Could Successfully Unite Gravity and Quantum

Multiple Choice

In the string theory that could successfully unite gravity and quantum mechanics, the universe must have

A) four dimensions (three spatial and one temporal) .
B) six dimensions (three spatial and three temporal) .
C) seven dimensions (six spatial and one temporal) .
D) nine dimensions (eight spatial and one temporal) .
E) eleven dimensions (10 spatial and 1 temporal) .