TMS320F28388D: Which is best for Unsed ADCINxx and VREFxxx pin?

Tool/software:

Dear Sir/Madam,

How are you doing today?

I use TMS320F28388D for EtherCAT slave project and I just used 2 ADC(Single-ended) port in F28388D.

1) Used: ADCINA0, ADCINA1, VREFHIA, VREFLOA

2) Unused: ADCINA[2..5], ADCIN14, ADCIN15, ADCINBx, ADCINCx and ADCINDx

In this case which choice is best for F28388 application circuit.

1. unused analog port pullup to VDDA

2. unused analog port pulldown to GNDA

3. unused analog port to floating

Thank you.

Hyeon-Cheol Park