I doubt if you will find many CCC’s that offer a class similar to 10a. And if they do, UCSB may not recognize it as being equivalent.
UCSB offers 10a in a 6-week summer session. Anyone can enroll in the summer session. A prospective student could take the course during the summer between their first and second years at a CCC. Thus, before applying to UCSB they would know whether they got the necessary B grade. That might be a relatively expensive option since you would have to get an apartment in the UCSB area for a couple of months, but it might be better than enrolling at UCSB without knowing if you would get into your preferred major.
Also, students at Santa Barbara City College can take one class a quarter at UCSB. Thus, they could take the course any quarter before applying.