What will life in the future be like?Will it be much better

What will life in the future be like?Will it be much better than it is now?And what will we be able to do in 1020 or 30 year's time?
Genetic engineering(基因工程) may help us make the perfect human.Babies may grow up to play basketball like Yao Ming or look like Cecilia Cheung.Also,we may be able to bring the dead back to life.Maybe people will be able to meet and talk with their dead family members.
Over the next 20 to 50 years,it will become harder to tell the difference between humans and machines.
Perhaps we will be able to make copies of ourselves,so we will appear to be alive long after we are dead.People may be able to find ways of putting the life of a person into a new body.
Narobots(纳米机器人) will be important.We will use them when we are sick.For example,when we have a stomachache,we will swallow(吞下) a narobot and it will travel through our stomach,taking a video of what's happening there.The video will help the doctor heal(治愈)us.
In the future,computers may have their feelings.They may be able to think betterr than us.We may be more and more interested in computers and the Internet,spending all our time in front computers.Perhaps we will forget our real needs.Perhaps we will become super couch potatoes weighing 250kg!
请问:It may be harder to tell the difference between humans and machines because ______.
A.we may be able to make copies of ourselves.
B.body parts will be replaceable by machines.
所给答案是B.答案A为什么不行呢?

A只是说我们可能克隆出自己.与题意不符.
问题是：区分人类与机器人可能会更难一些因为
所以B对