How is the n value of the d sublevel of a f-block element related to the period number of the element?

Question

$\begin {array} {1 1}\text{It is always two less than the period number value} \\\text{It is equal to the d value} \\\text{It is greater than the period number by one} \\ \text{It is always one less than the period number value}\end {array}$