The correct answer is A. Reveal.
To reveal something is to make it known or visible. It can also mean to expose something that was previously hidden or secret.
To explore something is to investigate it or travel through it in order to learn more about it.
To conceal something is to hide it or keep it secret.
To strip something is to remove its covering or outer layer.
In this case, the word “divulge” means to make something known or public. This is most closely related to the word “reveal,” which also means to make something known or visible. The other options do not have the same meaning as “divulge.”