Step 1: Understanding triple talaq.
"Instant triple talaq" (talaq-e-biddat) allowed a Muslim husband to instantly divorce his wife by pronouncing "talaq" three times.
Step 2: Legislative change.
In 2019, the Parliament passed the Muslim Women (Protection of Rights on Marriage) Act criminalizing this practice, making it void and illegal.
Step 3: Eliminate incorrect options.
(a) & (b) relate to other aspects of Muslim personal law.
(d) Special Marriage Act is for civil marriages.
\[
\boxed{(c)}
\]