573 - Logical Reasoning

A study of a math program implemented in several pre-schools indigrees that children who received the specialized Math Plus math edugreion between the ages three and five had significantly higher math scores in 3rd and 4th grade than their classmates who did not receive this instruction. The proponents of the math argue that the introduction of this program for all children age three to five will significantly improve their chances for success in school.
Which of the following, if true, would most seriously weaken the above argument?

1. Most parents send their children to preschool for social development and do not have a clear idea about what types of edugreion they want for their children.
2. Cognitive abilities of 3- to 5-year-old children are constantly changing.
3. The children in the pre-schools that were studied had previously been exposed to another math enrichment program.
4. Children are not really interested in enrichment programs in preschool.
5. The cost factor needs to be specified and established before a large scale program can be undertaken.