Final answer:
The correct replacement for the underlined word "Scanning" is "scans," which maintains the same tense as the original sentence.
Step-by-step explanation:
The best replacement for the underlined word "Scanning" based on the options provided would be "scans". The word "scanning" indicates present continuous tense, which suggests an ongoing action. When choosing a replacement without additional context indicating a change in tense, the simplest present form of the verb, "scans," should be selected to maintain the same tense. Therefore, the correct answer is (c) "scans".