Final answer:
The truth table for Statement 1B has four lines.
Step-by-step explanation:
The truth table for Statement 1B has four lines. To construct the truth table, we list all possible combinations of truth values for the variables B and R and evaluate the logical expression 1B(R • B) ≡ (B ⊃ ∼ R) for each combination. Since we have 2 variables, B and R, and each variable can take 2 possible truth values (true or false), the total number of lines in the truth table is 2 × 2 = 4.