The correct option is C diplotene
Synapsis is the pairing of two homologous chromosomes that occurs during meiosis. It allows matching-up of homologous pairs prior to their segregation, and possible chromosomal crossover between them. Synapsis takes place during prophase I of meiosis.
Prophase 1 of meiosis is the first stage of meiosis and is defined by five different phases; leptotene, zygotene, pachytene, diplotene and diakinesis.
Pachytene is the stage during which synapsis occurs and the cell enters the stage called diplotene. Diplotene is the stage during which the paired homologous chromosomes begin to separate.