What was said in the lectures regarding how secure children in Japan might use their caregiver as a secure base, as compared to secure children in the USA?

a. Secure children in Japan will wander away from their caregivers and explore their environment confidently, just as secure children do in the USA.
b. Secure children in Japan will wander away from their caregivers and confidently explore the surrounding environment; on the other hand secure children in the USA will confidently explore their relationship with their caregivers.
c. Secure children in Japan will confidently explore their relationship with their caregivers; on the other hand secure children in the USA will wander away from their caregivers and confidently explore the surrounding environment.
d. Secure children in Japan and the USA will both confidently explore their relationship with their caregivers, and in both cultures secure children will not wander away from the caregiver.