According to string theory, six space-time dimensions cannot be measured except as quantum numbers of internal particle properties because they are curled up in size of the order of:

According to string theory, six space-time dimensions cannot be measured except as quantum numbers of internal particle properties because they are curled up in size of the order of:
A)1035 m.
B)1015 m.
C)1010 m.
D)108 m.
E)103 m.