It’s parents’ worst nightmare. Their child doesn’t come home one evening and is missing for several days.    
When a 14-year-old boy from Atlanta, Georgia disappeared earlier this year, his mother turned to her Smartphone for clues using an app（应用程序） called Family Tracker that helped track his location.
“You can see where your loved ones are without having to call or bother them. ”said Roberto Franceschetti of LogSat, the creators of the Family Tracker, which has more than 100,000 users and is available worldwide.    
Parents can track the location of their child on a map, send messages, and even sound an alarm on the phone in a long distance.
“We have an option for the sender to make a very unpleasant, noisy sound. It’s a loud alarm and we repeat that sound every two minutes until the person picks it up, ”he said.
Parents don’t need to own a Smartphone to track their children. The service is also accessible through the web, as long as the phone that is being tracked is running the app.
Family Tracker has an additional service that keeps records of all data from the app for a two-week period, which the company calls GPS breadcrumbs.
“With a subscription（预定）, we keep all the locations where people have been on our servers. You can see where your kid has been for the past two weeks. You can find out where someone was at a certain time or when that person was at a specific place, ”Franceschetti explained.
“When somebody gets abducted（劫持）, usually whoever does this throws the phone away or takes the battery out. We were hoping that our app would at least provide information on where the person was abducted or where they had been in the past. ”
But will these types of apps let out personal secrets?
“The advantages are huge compared to the disadvantages. Let’s not forget that the person always has to give initial permission—no one can be tracked unless they allow someone to do it. ”said Franceschetti.
According to the passage, all of the following about “Family Tracker” are true EXCEPT that __________.

A．it can help parents know where their children are

B．all parents don’t need to own a Smartphone to track children

C．parents can use all the services of the app for free

D．it has little to do with letting out personal secrets

What can we infer from the passage?

A．The app will enjoy a great popularity in the future.

B．The loss of children won’t be a nightmare for parents any more.

C．The app will repeat the loud alarm continuously whenever parents track children.

D．The app can keep records of information for more than half a month.

Which belong to the functions of the new app?
a. track location      b. detect criminals    c. send messages
d. protect privacy     e. send remote alarm   f. record information

A．a, b, c, e

B．a, c, e, f

C．a, c, d, e

D．a, d, e, f