I agree that most likely a reference to an Immigration Service regulation promulgated as a result of the Immigration Act of 1917.
The Act contains the following language:
The following persons shall be excluded from admission:
"All aliens over sixteen years of age, physically capable of reading, who cannot read the English language, or some other language or dialect, including Hebrew or Yiddish: Provided, That any admissible alien, or any alien heretofore or hereafter legally admitted, or any citizen of the United States, may bring in or send for his father or grandfather over fifty-five years of age, his wife, his mother, his grandmother, or his unmarried or widowed daughter, if otherwise admissible, whether such relative can read or not; and such relative may be permitted to enter."
Olga was apparently sent for by her father who had previously been legally admitted. He paid her fare and his residence is her destination. That apparently makes her eligible for this exemption.
There is an anomaly in the record. If the typewritten numbers for her age represent "13" then she should have been marked "Under 16" in the leftt margin and she would not have been subject to the literacy test nor required an exemption.