we grow our own fruit and vegetables,---saves money of cours

答案是：a,which.
理由：这里前面整句话做先行词,这里并没有表示“正如”,而是代指前面整件事情
as,which引导非限制性定语从句的区别：
在非限制性定语从句中,as和which都可以作为关系代词使用,但是注意下列区别： 
1、which引导的非限制性定语从句不能放在句首.
2、as引导的非限制性定语从句一般有“正如”的意思,而且不能与主句的意思相悖.
     √ He reads English every morning,which is very natural.
     ×Which is very natural,he reads English every morning.
    The meeting was put off,which was exactly what we wanted.（which指代前面整个句子,且没有正如的意思）
      He remarried,as was expected.
      He remarried,which was unexpected.
      As is known to all,water freezes at zero.