Pengaruh pengetahuan, tingkat pendidikan dan pendapatan terhadap preferensi nasabah dalam mengambil keputusan menjadi nasabah Bank Syariah (studi kasus nasabah PT. Bank Muamalat Indonesia Cabang Sudirman Jakarta Pusat) = The effect of knowledge, education level and income to customer preference to decide to become Islamic Bank Customers (in case studies of PT. Bank Muamalat Indonesia Sudirman branch, central Jakarta)