Diego is in the Strange Situation with his caregiver; he explores the room and examines the toys that have been placed in it. He uses the caregiver as a secure base from which to explore the room. He would be classified as being .a. Insecure resistant
b. Insecure avoidant
c. Securely attached
d. Insecure disorganized

c. Securely attached.

Explanation:

In psychology the term Strange Situation was a procedure developed in the 70's where children were left alone in a room with a caregiver and toys and the behavior of the children was observed and, depending on this, they were classified in different types depending on the way they behaved (this was a measure of their attachment)

The securely attached children were confident enough that the attachment figure (the caregiver) would satisfy their needs so they would explore across the room and used the caregiver as a safe base to return to when they feel like they needed to.

In this example, Diego is in the Strange Situation and he explores the room and examines the toys that have been placed in it. He uses the caregiver as a secure base from which to explore the room. We can see that he fills the requirements to be classified as a securely attached children, since he is exploring the room and the toys and uses the caregiver as a safe base.  

answer; (d) one tectonic plate plunges beneath another; (most common,convergent boundaries)

the answer your looking for is c. : )