The researchers selected 16 November-old children for experimental research. Eight of them came from English-speaking families, and the other eight came from Spanish-speaking, English-speaking families. Each child listened to an audio recording about 18 minutes long. Both English and Spanish are pronounced. Researchers have used magnetoencephalography to find that in the brain's executive region, children who grew up in bilingual families responded more strongly to verbal sound stimulation than children in monolingual families. Strongly, this shows that the bilingual environment has begun to affect brain activity very early. Which of the following, if true, best supports the above conclusion? ['Comparatively speaking, Spanish sounds more pronounced on the brain than English.', 'Children who have grown up in a bilingual family can master bilingualism without the need for parents to teach it.', 'Children of bilingual families at 11 months of age have a stronger perception of foreign language sounds than when they are 6 months of age.', 'Previous studies of the human brain have shown that adults with bilingual skills have more active brain functions.']