Hi all, I just sent my Vios to the service center yesterday and found out that my front right tyre has a small bulge at the side (probably hit a divider or smtg). I'm thinking of replacing it but not sure which are the better options:

1) Replace the bulged tyre with the spare tyre (they're the same size if i didnt check wrongly) and continue using the car. The bulged tyre kept as spare.
    - since I don't drive my car much (2 years+ in, about 12k mileage), was thinking if i can do this?

2) Replace the bulged tyre with the spare tyre, go change the bulged tyre and keep as spare.
    - with this then i can utilize the spare tyre all all 4 of the wheels are same brand

3) Drive to tyre center and change the bulged tyre straight (spare remain as spare, not touching).

Of all 3 options, which one do you think is the better, safer option i should do? Not sure if just changing 1 front tyre is advisable? I checked the condition and thread of the other good tyre and it is still in good condition (can use maybe another 2 years?) Quite a noob in car so really appreciate the help of all the sifus here.