A bivalent meiosis-I consists of

1.  two chromatids and one centromere

2.  two chromatids and two centromeres

3.  four chromatids and two centromeres

4.  four chromatids and four centromeres

Class 11 pg 168
(c) The complex formed by a pair of synapsed homologous chromosome is called bivalent or a tetrad. It has two centromeres and four chromatids.
Rest of the options are incorrect.