Final answer:
The correct answer is option c. Anti-war protests outside it turned into massive riots following the arrival of police.
Step-by-step explanation:
The 1968 Democratic National Convention in Chicago was a notable event for several reasons, not least because it became a flashpoint for protests and civil unrest. The correct statement that describes the convention is that anti-war protests outside it turned into massive riots following the arrival of police. The convention saw a considerable police presence, with 12,000 Chicago police officers and additional National Guardsmen deployed to maintain order.
The police actions against protestors were aggressive and violent, which later became known as a "police riot." The convention was also marked by internal conflicts within the Democratic Party as they debated a new antiwar platform, eventually nominating Hubert Humphrey as their presidential candidate. Richard Nixon was not nominated at this convention; rather, he was the Republican nominee and later won the presidency.