How does "On your next turn, this attack does x more damage" work after Turn #2?

[Zimbu]

How do attacks with special conditions that say "on your next turn, this attack does x more damage" work? For example, M Blaziken EX (XY Promo 86) has the following attack:

Moonsault Blaze - 100
During your next turn, this Pokémon's Moonsault Blaze attack does 100 more damage (before applying Weakness and Resistance).​

Assuming the Pokemon remains active and uses Moonsault Blaze on every turn:

Turn 1: 100 Damage (100 Base)
Turn 2: 200 Damage (100 Base + 100 More)
Turn 3: ???
​

How is the damage interpreted for Turn #3? Is it:

a. 100 Damage (100 Base) (the "100 more damage" from Turn #1 wore off, Turn #2 text does not apply)
b. 200 Damage (100 Base + 100 More) (the "100 more damage" from Turn #1 wore off, but the "100 more damage" from Turn #2 applies)
c. 300 Damage (100 More than Turn #2) (ie: the "100 more damage" means 100 more than the previous turn)​

Magearna EX (Steam Siege 75) has similar text for Soul Blaster - 120 that says "During your next turn, this Pokémon's Soul Blaster attack's base damage is 60." So if I just keep attacking with Soul Blaster over and over, does the base damage stay at 60 forever from Turn 2 and beyond?

 

[PokePop]

It is b.
The old effect from two turns ago only lasts for the one turn (as described) but the new effect from the last turn applies, so it does 200 damage.

Yes, if you used that attack last turn, then the next turn it would do 60. Unless you play Pokemon Ranger or switch it to the bench and then bring it back up. Or something else like that which removes attack effects.