A study of young children's ability to learn foreign languages found that those with parents who read them more than one book per week in their native language were 75% more proficient in the foreign languages that they learned than children whose parents read them one book per week or less. A secondary finding of the study was that children's ability to remember new vocabulary in a second language drops off sharply after the age of 6, when it becomes 75% more difficult to retain new words learned in the second language.

Assuming the statements above are true, which of the following can be inferred from them?

A:The ease of learning a second language depends almost exclusively on environmental factors.

B:A student whose parents only read one book a week to her only has a 25% chance of mastering a foreign language.

C:Students whose parents enter them in early education and who read to them frequently are more likely to have extra income and more free time.

D:Proficient speakers of a second language are likely to have begun learning it before the age of 6.

E:Students who begin studying a language later in life would have had an easier time learning some aspects of that language if they had begun studying it as a young child.