Which of the following is true ?

Question

$\begin{array}{1 1} \text{(a)Fluorine is assigned the oxidation state of +1 in all compounds } \\ \text{(b) In the formula of a compound , the algebraic sum of the oxidation states is never zero} \\ \text{(c) Oxygen's oxidation state in most compounds is -1 } \\ \text{(d) Oxygen can have an oxidation state of -1} \end{array}$