I'm now  considering whether to pledge FD since my initial application is not successful. 30k should be OK.

Sorry... Utility no CB .Only grocery and dining.

So for pledge FD, after 1 year I am able to withdraw the FD money; with the PB Visa Signature credit card still active to use? 

If your income is >100k then you are free to unpledge after 1 year

wei only 100k annually can apply? what is the minimum?

For Public Bank Fixed Deposit (FD) customers who opt to apply PB Credit Card secured
by FD, the credit line assigned will be based on the FD pledged amount at a ratio of 1:1.
To apply, please personally submit your application at your FD account holding branch
and bring along your FD certificate for verification and photostat copy of your NRIC (both
sides).

https://www.pbebank.com/pdf/Cards/Visa-Sign.../signature.aspx