50. In application layer protocols including HTTP, SMTP, and FTP, what mechanism is usually used to translate the host name provided by the user into an IP address?
(A) FTP
(B) Database
(C) DNS
(D) IMAP
(E) None of the above

46. Which of the following statements is incorrect for the transport layer? (A) TCP is a reliable and connection-oriented protocol (B) TCP uses the IP address (C) UDP is not a reliable and connection-oriented protocol (D) UDP does not uses the IP address (E) None of the above

47. Which of the following statements is incorrect for the Ransomware?(a) It is a type of denial-of-service attack(b) It will encrypt the files to prevent the access(c) It will lock the computer to prevent the normal usage(d) It often uses phishing as an entry point (A) (a) (B) (b) (C) (c) (D) (d) (E) (b), (d)

48. Which of the following data structures is in LIFO (Last In First Out) order? (A) Array (B) General Array (C) Stack (D) Queue (E) Double Queue

49. If users including individuals, organizations, and enterprises can obtain computing, computing power, and shared software and hardware resource application services through the Internet, which of the following computing modes belong to the above statements? (A) Client/server (B) P2P (C) Broadband (D) Decentralized (E) Cloud

51. Assume the execution time of a running program is 50(logn2) + 8, then what is the most suitable time complexity? (A) O(logn2) (B) O((logn)2) (C) O(logn) (D) O(n) (E) O(n2)

52. According to the definition of the major topics of information ethics, "When can information be used for free? Under what circumstances should it be used with a payment or with the consent of the owner?" What does this statement mean? (A) Accessibility (B) Accuracy (C) Privacy (D) Property (E) None of the above

53. Which of the following statement is not the responsibility of an operation system? (A) Communicate with the computer user (B) Manage allocation of memory (C) Collect input from input device (D) Execute the program (E) Convey program output to the output device

54. Which of the following data type conversion may result in data loss? (A) float to double (B) int to char (C) short to long (D) int to float (E) bool to char

55. Which of the following statement is true? (A) A NOT gate accepts two inputs (B) The output of an XOR gate is O unless both inputs are 1 (C) The sum of two binary digits (ignoring the carry) is expressed by an OR gate (D) The NOR gate produce the opposite results of the XOR gate (E) Inverting the output of an AND gate is equivalent to inverting the individual signals first, then passing them through an OR gate

56. Which of the following is NOT essential for a time-sharing operating system? (A) Interrupt vectors (B) Privileged instructions (C) Memory protection (D) Virtual memory (E) Dual mode processor state