Answer: Option a, si
Explanation: The reading is missing, but ill try to answer it anyway.
The statement says:
"Las señoras suelen ir al mercado municipal un día a la semana."
and this can be translated to:
"The ladies usually go to the municipal market one day a week."
This is usually true, it is common to do one big purchase per week, with the objective of saving time later, especially because the municipal market may not be close for everyone, so it is safer to do a big purchase one day, and if in the week something is running of, they can buy it in the closest market.
So the correct option is a) si, that means "yes"