Who should get the ward gold?
Solution 1:
In an ideal situation you would let the ADC get the gold, for the same reasons you let the ADC get the gold from minions. It's more important to get the ADC fed so that they can do their job and do tonnes of damage. Why would you give them minions/monsters but not the ward gold?
However I think it's dependant on the situation.
If the enemy pinked the lane bushes for some reason (usually an in lane gank, or your team has a stealth jungler). In this situation the ADC is near the pink ward and can easily hit it without missing minions.
But in the majority of cases the ward is going to be in the tri bush or river bush. Meaning that the adc may miss a minion to go attack the ward. Another issue with the adc leaving lane for a pink ward is that it puts them out of position the enemy duo may do something or the enemy jungler/mid could be around, so it would be better for just the support to die then both of you dying over 30 gold. The enemy duo could also push the wave hard meaning that you would have to either run through the enemy wave, adc and support (aka suicide) or go the long way round to your tower. (more common if you're top right).
It all depends, these are just some things to take into account.
Solution 2:
I agree with Aequitas, generally it's better if your ADC takes the gold, obviously if your ADC is busy farming, the Supp will take care of it, besides, thats another little income for the Supp every now and then. What is ideal to do and I try to do it as often as possible is, for both of u to get gold out of it. If your Supp uses the Sweeping lense or he puts a pink ward (well...Control Ward) near an enemy ward and the ADC destroys it, it'll give full gold to the ADC and some gold (not sure how much, i think its 5 or 3) to the Supp, it's like a Ward Assist.