Practice question

Go with B — ψs, ψp and ψg. Under PSS- Sec-F-Transport, this is the standard explanation you’d use in class: it names the real driver or definition, while the rest are nearby but wrong. Not these: A) ψs and ψp only; C) ψp and ψg only; D) ψs and ψm only. When two options sound similar, choose the one that matches the textbook definition most tightly.