The function len(race) returns the number of items or elements in the race object. Without knowing the specific contents of race, it's impossible to determine the exact value it would return. In Python, if race is a list, tuple, set, or other collection types, len() would provide the count of elements contained within those objects.
From the options provided—3, 10, 4, and 9—any of these could be correct depending on the actual data held in race. Please check the number of elements in the race object to determine the appropriate response.