What wireless networking term describes the increase of RF energy in an intentional direction with t

What wireless networking term describes the increase of RF energy in an intentional direction with the use of an antenna?

A. Directed Radiation

B. Active Amplification

C. Passive Gain

D. Beam Digression

Reference: https://books.google.com.pk/books?id=saC_2j-IwwIC&pg=PA51&lpg=PA51&dq=passive+gain+increase+of+RF+energy+in+an+intentional+direction+with+the+use+of+an+antenna&source=bl&ots=ePmfHdkUks&sig=TzpBqUuomGckVXy6kPAO8t2l_Jc&hl=en&sa=X&ved=0ahUKEwjwtb6Ds57ZAhUBesAKHfpCCSAQ6AEIKjAB#v=onepage&q=passive%20gain%20increase%20of%20RF%20energy%20in%20an%20intentional%20direction%20with%20the%20use%20of%20an%20antenna&f=false