Upgrading (Downgrading?) Mini-ITX Cooling; Need More Silence

Currently running an H100i w/ stock fans in a Corsair 250D (+ GTX 980, i5 4670k, AX760 PSU) and I'm thinking of remodeling to something much quieter. Frankly, this dual-rad is great but it really commands a lot of interior room (in this case specifically) and truthfully I really don't need nor strive to achieve those few extra degrees of cooling power. As of right now, I have a couple options. Note that because the 250D is a mini-ITX case, I have to plan for a cooler that fits the height requirement (< 150mm) as well as clears the RAM slots.

At the moment I'm running my 4670k @ 4.2 (from stock 3.4) with no problems, though I'm not a serious gamer nor an overclocking enthusiast. I have no future plans to increase its speed but there's always the possibility I might (but not by much).

In terms of what my priorities are when looking for new cooling, I would have to say; low noise first, performance second, then aesthetics.

Should I..

A - Keep H100i and replace it's stock fans with Noctuas (or other comparable fan)

B - Sell H100i and replace with a single rad AIO and quieter fan

C - Sell H100i and replace with air cooler (Noctua NH-U9S or other Noctua, Cryorig C1 or H7, Scythe, etc.)

D - Something else?