Answer :
D - It has been proven false. A majority of people use computers on a daily basis.
Answer:
b. It is not current
Explanation: The answer that most clearly explains why Joohn Howatd's statement is not credible today is D. The reason is that saying that computers are not as simple as to be used by common citizens was credible in 1975 but it is an obsolet thinking nowadays. In the present almost every citizen knows how to use a computer because technology has developed a lot during the past decades and computers are part of citizens' daily lives.
The other options are not correct because the statement does not contain personal opinion and because it was accurate when he said it.