Factor t12 – r3s15.

Recognize a difference of cubes: t¹² = (t⁴)³ and r³s¹⁵ = (rs⁵)³. Using a³ − b³ = (a − b)(a² + ab + b²), with a = t⁴ and b = rs⁵, gives (t⁴ − rs⁵)(t⁸ + rs⁵t⁴ + r²s¹⁰). This matches choice B.

AI-written and checked against the verified answer.