Which option represents the correct sequence of events during callus culture?

• A
  Explant $\rightarrow$ Callus $\rightarrow$ Cell division $\rightarrow$ Addition of cytokinin $\rightarrow$ Cells differentiate into meristematic tissue.
• B
  Explant $\rightarrow$ Callus $\rightarrow$ Cell division $\rightarrow$ Addition of cytokinin $\rightarrow$ Cells differentiate into meristematic tissue.
• C
  Callus $\rightarrow$ Explant $\rightarrow$ Cell division $\rightarrow$ Addition of cytokinin $\rightarrow$ Cells differentiate into meristematic tissue.
• D
  Explant $\rightarrow$ Cell division $\rightarrow$ Callus $\rightarrow$ Addition of cytokinin $\rightarrow$ Cells differentiate into meristematic tissue.