Yes 14 would be B
Just eliminate options
Covalent nature increases as size of anion increases and as covalent nature increases, melting point decreases
Also option is misprinted. Put < sign instead of =
15 d @Aayush
In 8th period there are 5g,6f,7d,8s,8p orbital. s orbitals are 1, p orbitals 3, d orbitals 5 and f are 7 in number and g are 9.
If the orbital contain 3 spin quantum number, then each orbital can hold 3 electrons instead of 2. Adding one electron each will lead to new element. So total elements are
5g=9 x 3 + 6f = 7 x 3 + 7d =5 x 3 + 8p = 3 x 3 + 8s=1 x 3 = 75