The Following Two Statements Refer to Conducting Research Via the Mail

Multiple Choice

The following two statements refer to conducting research via the mail.
I.One strength of mail surveys is their high response rate.
II.Mail surveys should be avoided when the questionnaire is long and/or complex.
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