Time Warner Cable Inc. rejected an acquisition offer from Charter Communications Inc. valued at more than $61 billion including debt, spurning the biggest unsolicited takeover bid since 2008. Time Warner Cable Chief Executive Officer Rob Marcus called the $132.50-a-share bid a “low-ball offer” in an interview yesterday. The proposal included about $83 cash per share and about $49.50 in stock, according to Charter. Excluding debt, the deal would be worth about $37.3 billion. Charter, backed by billionaire John Malone, is seeking to create a provider of TV, Internet and phone service for about 20 million subscribers in 38 states. The combined company would be the third-largest pay-TV operator by customers — behind Comcast Corp. and DirecTV — helping it generate cost savings and negotiate better programming deals.