Which concurrency control technique uses read and write

Statement: P < Q; V < S > T; V < U > Q

Conclusion: I. T ≥ P           II. P > T

Which of the following symbols should replace the question mark (?) in the given expression in order to make L ≤ N definitely true?

Statement: F < G < H ≥ J; F ≥ K > L

Conclusion:

I. H > L

II. H = L

Statements: A > Y = D > Q, M ≤ B > P > Y

Conclusion:

I. Y ≤ M

II. B > Q  

Statements: C ≤ A ≥ B > D; F > E ≥ G ≥ A

Conclusions:

I. E ≥ B

II. F > D

Statements: X > O > D; T > M ≥ O; X > R

Conclusions:

I. T > R

II. R < D

Statements: D > C ≥ A ≤ B = F, G ≤ K < L < C

Conclusion:

I. D > G

II. C > G

III. K ≤ B  

Statements: E ≥ F ≥ A ≤ W, N ≥ M ≥ Y = E

Conclusion:

I. N > W

II. Y ≥ A

Statements: M ≤ N = O ≤ P; P = Q ≤ U; R > N = U

Conclusions:

I. R > O

II. U ≥ M

Statements: Z > Y ≥ X; I < N ≤ L; F < I > D > Z

Conclusions:

I. L > F

II. X < N

III. Y < I