To identify the nuclear pore in an animal cell based on the provided letters, it's important to have a visual reference or diagram. However, without seeing the actual diagram referenced by the letters a, b, c, d, F, and I, I can't definitively tell you which letter corresponds to the nuclear pore.
Typically, in diagrams of animal cells, the nuclear pore is usually marked or labeled specifically. If you have the diagram in question, you might typically look for an opening in the nuclear envelope or a structure that looks like a complex surrounding the nuclear membrane.
If you can provide more context or details about the diagram, I could help make a better guess!