Answer:
B
Explanation:
Rc =6.7×10^-11 and Rs=1.9×10^-10
since power of 10 is negative in both hence greater the magnitude of power lesser is its value
hence Rc is less than Rs
ratio of radius of atom of sodium to radius of carbon = (1.9×10^-10)÷(6.7×10^-11)
=2.84
hence B