Option C is closest. What zone do you live in? Is this cool season grass?
The least expensive but far more intensive laborious is getting a rake, a hoe and ripping the dead stuff off of the soil. If you are familiar with line trimmers, I would scalp these yellow spots down to the ground...mow with a rotary mower to suck up debris. Bag the debris and put in your compost.
Using a rotary seed spreader spread professional (cool season grass mix zero weed seed). Firm the entire lawn with the back of a leaf rake. Water enough to wet the top of the soil 1/2 inch.
Never use weed and feed anything. Remember that. Your lawn will come around doing nothing more than these instructions. Save your money up to get a sod cutter and remove the entire lawn and lay fresh new sod. No weed and feed.
Never mow below 3", 3 1/2 " is best!
Once you've done your first mow, let the soil dry out a bit. Step on your grass and if and only if the blades stay down then water, and water down at least 2". Let dry until you see your footprints on the the grass. That is the sign to water and water deeply. Don't water until the blades of grass are dehydrated and your footprint stays down.
Aerate once per year by pulling plugs of sod/soil out of the lawn and leaving them where they fall. Rent a machine with your neighbors.
Sharp sharp sharp blades.
Bag your clippings and use them in the compost pile or thinly on the back of plant beds.
While the seed is germinating, only water 1/4 inch to 1/2 inch. Not soggy just moist. You will have to water at least 4 or 5 times on a hot day, a cool day, not so much. Don't allow that seed bed with the germinating seeds to dry out.
After 11 days to 14 days , with decent spring weather, warmth, you should do your first mow. BAG those clippings. This is also the time to do your first fertilizer application (4 per season usually). My favorite even as a commercial lawn person was Dr. Earth's Lawn Fertilizer. A bit more expensive but lasts longer, extended release...also thatch eating bacteria and mychorrhizae fungi. Only 3 applications per season. Amazing stuff.
If this is your home save up for a professional but simple landscape. Raises the value of a home more than a remodeled kitchen or an added bathroom. Hope this revives your lawn. Grins, follow the instructions and you'll be impressed. Mow no lower than 3 to 3 1/2 "! Get a manual 'lift' kit for your mower. Lots of mowers are unable to mow at this height. Warm season grass is very different. Any shorter for cool season grasses and you'll be back where you started.
How long ago did you use this non specific grass and weed killer? You will have to wait at least 3 to 4 weeks to use any seed.
Another option is to get a bid from a grass seed company. They will outline exactly what you can do to get ready and then they spray seed and mulch and guarantee the grass growing. They work with you and closely. Bids are free. Sure learn a lot and get options that you might not have considered.