Case 1: \(c\) is satisfiable

• Case 1A: \(\ell_1 = 1\) or \(\ell_2 = 1\)
  
• Case 1B: \(\ell_{k - 1} = 1\) or \(\ell_k = 1\)
  
• Case 1C: \(\ell_i = 1\) with \(i \not\in \{1, 2, k - 1, k\}\)