At which stage does the number of homologous chromosomes become halved?

The complex formed by a pair of synapsed homologous chromosomes is called,

The term '$meiosis$' was given by

Which of the following phases is the longest phase of Meiosis-$I$?

Assertion : Diplotene is characterized by the presence of chiasmata.
Reason : Diplotene can last for months and years in oocytes of some vertebrates.

What is the name of the transitional stage between $Meiosis-I$ and $Meiosis-II$?