How S1 is true? in the linked shared by you it is written that:

"In turing machine if we increase the number of tape then also language accepted by that machine is same as single tape turing machine.so there expressing power is same."

So how it makes S1 true? I think correct answer should be option B.

"In turing machine if we increase the number of tape then also language accepted by that machine is same as single tape turing machine.so there expressing power is same."

So how it makes S1 true? I think correct answer should be option B.