Answer:
the first sentence.
The first atomic bomb that exploded on the White Sands Proving Grounds, was posted in 1945.
Step-by-step explanation:
On 16 July 1945, the 'Trinity' nuclear test plunged humanity into the so-called Atomic Age. The first-ever nuclear bomb was detonated in New Mexico, at the Alamogordo Test Range. Nicknamed the “gadget”, the plutonium-based implosion-type device yielded 19 kilotons, creating a crater over 300 metres wide.
Significant events. The first atomic bomb (code named Trinity) was test detonated at Trinity Site near the northern boundary of the range on 16 July 1945, seven days after the White Sands Proving Ground was established.