a$.$ Which periods of the periodic table have $8$ elements?

$($Select all that apply.$)$

period $1$

period $2$

period $3$

period $4$

period $5$

period $6$

b$.$ Which periods of the periodic table have $18$ elements?

$($Select all that apply.$)$

period $1$

hiriod $2$

period $3$

period $4$

period $5$

period $6$

c$.$ Which period of the periodic table has $32$ elements?

period $1$

period $2$

period $3.$

period $4$

period $5$

period