Step 1: Analyze the relationship between the two clauses. There is a contrasting relationship (heavy traffic vs. arriving with plenty of time). Step 2: Eliminate incorrect options. "Because of" and "Since" show cause and effect, which does not fit here. Step 3: Choose between "Although" and "Despite". "Although" must be followed by a full clause (subject + verb), e.g., "Although the traffic was heavy". "Despite" is followed by a noun phrase ("the heavy traffic"). Answer: Despite