Final answer:
Procrastination is included on the list of big killers of financial success because it can undermine long-term wealth accumulation, while frugality and wise investments are behaviors that support financial success.
Step-by-step explanation:
The big killers of financial success that you should watch out for do not include positive behaviors like frugality or making wise investments. Instead, one of the main threats to building wealth is procrastination. This is because delaying saving and investing can potentially undermine wealth accumulation over time. In contrast, behaviors like frugality and delayed gratification actually support financial success, as they entail making sacrifices now to reap greater benefits later. Similarly, wise investments contribute positively to financial success by helping to grow your savings and overall wealth. Therefore, the correct answer is C) Procrastination.