Droll & Lock Bird question

[woltarr]

STBL-EN082 Droll & Lock Bird
WIND/Spellcaster - Effect/1/0/0
If your opponent adds a card(s) from their Deck to their hand, except during the Draw Phase, you can send this card from your hand to the Graveyard. For the rest of this turn, neither player can add card(s) from their Deck to their hand. (Drawing cards is also considered as "adding a card to the hand.")

my question is:

a) AFTER the act of adding a card to the hand is concluded, you can activate this card effect. THEN for the rest of the turn, adding cards to the hand is proihibited

b) AFTER the ACTIVATION of the card that WILL add a card to the hand, you can activate this card. it will proihibite the oponent from adding a card to his hand AND for the rest of the turn, adding cards to the hand is proihibited

c) none above

d) all above

please let me know

thanks

woltarr

 

[Entropy]

(a) is correct.

For example, your opponent activates "Jar of Greed", and draws a card. Afterwards, you start a new Chain by activating the effect of "Droll & Lock Bird". After the second Chain finishes resolving, your opponent can no longer use effects like "Reinforcements of the Army" or "Allure of Darkness" or "XX-Sabre Darksoul" to add cards to his hand.