The statement that best compares the presidential and parliamentary systems is:
B) A presidential system and parliamentary system both have executives that are difficult to remove, and the legislatures are powerful branches of government. The main difference between the two forms of government is the separation of powers between the legislative and executive branches.
This option accurately reflects the key distinctions and similarities between the two systems, particularly highlighting the separation of powers in a presidential system contrasted with the interconnectedness of the legislative and executive branches in a parliamentary system. However, while the statement mentions that executives are difficult to remove, it's worth noting that this applies specifically to the president in a presidential system, while the prime minister in a parliamentary system can be more easily replaced. Thus, the answer has some simplifications but overall captures the essence of the differences and similarities effectively.