The Following Two Statements Refer to Response Rate

Multiple Choice

The following two statements refer to response rate.
I.Suggestions for increasing the response rate in mail interviews include
Using incentives at appropriate levels and using advance notification.
II.A long,detailed screener is likely to increase response rate in mall intercept
Interviews.
Which,if any,of these statements is (are) true?

A) I only
B) II only
C) I and II are both true
D) Neither I nor II are true