Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

Nowadays, most people realize that it’s risky to use credit card numbers online. However, from time to time, we all use passwords and government ID numbers on the Internet. We think we are safe, but that may not be true! A new kind of attack is being used by dishonest people to steal IDs and credit card numbers from innocent web surfers. This new kind of attack is called “phishing.”

Phishing sounds the same as the word “fishing,” and it implies that a thief is trying to lure people into giving away valuable information. Like real fishermen, phishers use bait in the form of great online deals or services. For example, phishers might use fake emails and false websites to con people into revealing credit card numbers, account usernames, and passwords. They imitate well-known banks, online sellers, and credit card companies. Successful phishers may convince as many as five percent of the people they contact to respond and give away their personal financial information.

Is this really a big problem? Actually, tricking five percent of the online population is huge! Currently, more than 350 million people have access to the Internet, and seventy-five percent of those Internet users live in the wealthiest countries on Earth. It has been estimated that phishers send more than three billion scam messages each year. Even by tricking only five percent of the people, phishers can make a lot of money.

Since there is so much money to make through this kind of scam, it has caught the interest of more than just small-time crooks. Recently, police tracked down members of an organized phishing group in Eastern Europe, who had stolen hundreds of thousands of dollars from people online. The group created official-looking email messages requesting people to update their personal information at an international bank’s website. However, the link to the bank in the message actually sent people to the phishers’ fake website. To make matters worse, further investigation revealed that this group had connections to a major crime gang in Russia.

How can innocent people protect themselves? Above all, they have to learn to recognize email that has been sent by a phisher. Always be wary of any email with urgent requests for personal financial information. Phishers typically write upsetting or exciting, but fake, statements in their emails so that people will reply right away. Also, messages from phishers will not address recipients by name because they really don’t know who the recipients are yet. On the other hand, valid messages from your bank or other companies you normally deal with will typically include your personal name.

Which of the following could best serve as the topic of the passage?

The course was so difficult that I didn't _________ any progress at all.