Do creatures that enter the battlefield at the same time see each other enter?
Summary: Option D is spot on. All three of your 1/1 are now 4/4 until end of turn (and your Commander is 5/5 until end of turn). 



The question has nothing to do with whether the tokens see each other enter the battlefield or not.* It's about how many creatures are on the battlefield when each of the triggered abilities resolve.

The game unrolls as follows, starting with Thatcher Revolt's resolution:


Thatcher Revolt places three creatures on the battlefield simultaneously. Goldnight Commander's ability triggers three times. [CR 603.2][CR 603.2c]
As a player is about to receive priority, you place Goldnight Commander's ability on the stack three times. [CR 603.3]
The third instance of Goldnight Commander's ability resolves: Creatures you control get +1/+1 until end of turn.
The second instance of Goldnight Commander's ability resolves: Creatures you control get +1/+1 until end of turn.
The first instance of Goldnight Commander's ability resolves: Creatures you control get +1/+1 until end of turn.


Three continuous effects were created by a triggered ability. They will only affect the creatures that existed when the abilities resolved [CR 611.2c], but all three of the 1/1s were on the battlefield when they resolved.

So all three of your 1/1 are now 4/4 until end of turn (and your Commander is 5/5 until end of turn).



&#42; &mdash; To answer your title question, yes. If you had two creatures with a triggered ability such as "When another creature enters the battlefield, ...", they would see each other entering the battlefield. This is codified by CR 603.6d: "Normally, objects that exist immediately after an event are checked to see if the event matched any trigger conditions. [...]"

For example, if two Goldnight Commander entered the battlefield simultaneously, both of their abilities would trigger [CR 603.6d], and both would end up getting +2/+2 until end of turn.