Lanthanides elements are -
| A. |
14 elements in the sixth period (at no. 90 to 103) that have 4f-subshell |
| B. |
14 elements in the seventh period (at. no. 90 to 103) that have 5f-subshell |
| C. |
14 elelments in the sixth period (at. no. 58 to 71) that have 4f-subshell |
 |
| D. |
14 elelments in the seventh period (at. no. 58 to 71) that have 4f-subshell |