The question is asking to state the element would most likely have chemical properties similar to that of fluorine and base on my research and further investigation, I would say that it would be Bromine. I hope you are satisfied with my answer and feel free to ask for more if you have questions and further clarifications
The correct answer is C. Colligative properties only depend upon the number of solute particles in a solution but not on the identity or nature of the solute and solvent particles. I hope this anwers your question.
I looked up what is the molecular formula for Phosphine and got this: PH3
Hope this helps! Let my know if this was correct.
