What are some capital guaranteed options for investment of $10,000?

Hey Anon, I'd recommend Etiqa Elastiq. Your capital is guaranteed and the current interest of 1.80% p.a is guaranteed for the next 3 years upon sigining up too. I've been using it for over a year, made many ad-hoc withdrawals and deposits with no penalties or whatsoever. Just note that there's a inital 3-month lockin period whereby you can't deposit or withdraw any funds. But it's much better than locking in for 3 years, such as an endowment plan.
https://www.tiq.com.sg/product/universal-life-i...

Singlife endowment plan requires a lockin of 3 years if I'm not wrong, for 2.25% interest p.a. If you do not need the funds then go for it. If you prefer the flexibility, consider Elastiq at 1.80% p.a. A year ago the interest rate was 2.02% and I'll be getting that rate for the next 2 years (since I've used it for 1 year).

Stashaway's Income portfolio isn't capital guaranteed and you might see losses especially during this time when most markets are in the red.

If you're a teen, consider Standard Chartered's JumpStart account at 2% interest p.a!

Singapore Savings Bond (SSB) are Endownment plans are good options. Go for SSB if you require liqudity as endownment plans usually require a longer lock in period.

Single premium endowment plan yes.
StashAway is not capital guarantee.

I only know that Singapore Savings Bonds and fixed deposits are capital guaranteed.