VCAA question

[Snorlax]

The answer is C
Restriction enzymes may be found within bacteria and they act as a defence mechanism, digesting viral DNA or RNA at a specific nucleotide sequence. EcoR1 = obtained from E.Coli bacteria
A restriction enzyme will 'digest' (cut) the phosphodiester bonds that form the phosphate-sugar backbone of DNA. As a result, the hydrogen bonds (weak) between the bases will also be broken.
Since we know that EcoR1 will only digest that DNA fragment at cutting site Q, we know that the smaller fragment will be 3 kb long.
We also know that BamH1 will only digest that DNA fragment at cutting site P, and that means the smaller fragment will be 2 kb long.
With this knowledge, we know that if both enzymes are added, the DNA fragment will be digested into 3 pieces. The total length of the DNA strand is 10kb. Thus, 2kb, 3kb and 5kb.

So, EcoR1 has 3kb and 7kb lengths of fragments. does this mean: 123.1234567 (. indicate the cut)
and BamH1 has 8kb and 2kb lengths of fragments, so 12345678.12

so together it would be: 123.12345.12?
Is that right?

(i kinda need to visualise it rather just stating it)

[psyxwar]

So, EcoR1 has 3kb and 7kb lengths of fragments. does this mean: 123.1234567 (. indicate the cut)
and BamH1 has 8kb and 2kb lengths of fragments, so 12345678.12

so together it would be: 123.12345.12?
Is that right?

(i kinda need to visualise it rather just stating it)

That's right. It's easier to just draw it out, though the answer to this is pretty obvious just from looking at it (has to be B or C, can't be B because the fragment that is 7bp long is digested at site P, meaning it has to be shorter than 7 (you also can't have a fragment smaller than 1bp in length, as the smallest one produced by p digestion isnt digested further). Only C is valid.)