Section A

26. [E] challenges

27. [J] searched

28. [D] categorizing

29. [K] similarities

30. [L] slightly

31. [G] percentage

32. [O] traditional

33. [I] regardless

34. [H] proving

35. [M] suggests

Section B

36. [I] It is possible for burglars to make jamming attacks with the necessary equipment and skill.

37. [D] Interfering with a wireless security system is similar to interfering with a conversation.

38. [J] A burglar has to continuously jam the wireless security device to avoid triggering the alarm, both inside and outside the house.

39. [F] SimpliSafe provides devices that are able to distinguish incidental radio interference from targeted jamming attacks.

40. [B] Only a very small proportion of burglaries are committed by technical means.

41. [H] It is difficult to crack SimpliSafe as its system keeps changing.

42. [C] Wireless devices will transmit signals so as to activate the alarm once something wrong is detected.

43. [K] Different measures should be taken to protect one's home from burglary in addition to the wireless security system.

44. [G] SimpliSafe's device can send a warning to the house owner's cellphone.

45. [E] Burglars can easily get a security device's frequency by Internet search.

Section C

Passage One

46. [B] He intends to get rid of the tipping practice.

47. [B] It adds to the burden of ordinary customers.

48. [D] They can have some say in how much their servers earn.

49. [A] Service quality has little effect on tip size.

50. [D] Waiters should be paid by employers instead of customers.

Passage Two

51. [C] The impact of cheap oil on global economic growth.

52. [D] Consumers will spend their savings from cheap oil on other commodities.

53. [C] They use their money reserves to back up consumption.

54. [B] Its negative effects more than cancel out its positive effects

55. [A] People are not spending all the money they save on gas.