The electron arrangements for two elements are shown below. element L: $2,8,8,1$ element M: $2,8,4$ Which line gives the group number and period number for element L and for element M?
- Aelement L: group I, period 4; element M: group IV, period 3
- Belement L: group I, period 4; element M: group III, period 4
- Celement L: group IV, period 1; element M: group III, period 4
- Delement L: group IV, period 1; element M: group IV, period 3