For the first part of your question regarding the phase of mitosis, you would need to provide a specific image or description of what you're seeing in order for me to help you identify the phase. Mitosis consists of several phases: prophase, metaphase, anaphase, and telophase.
For the second part of your question about cell differentiation, the most influential factor in determining how a cell will differentiate is the genetic information encoded in the DNA. While other factors like physical location and environmental conditions can influence differentiation, the DNA contains the instructions that ultimately determine the cell's fate.