The patterns of words and rhythms of the blues was standardized in the A. late 1700's. B. mid 1800's. C. early 1900's. D. in the late 1960's.

B - C ... mid 1800s to early 1900

Explanation:

Blues is a music genre and musical form which was originated in the Deep South of the United States around the 1870s by African-Americans from roots in African musical traditions, African-American work songs, and spirituals. Blues incorporated spirituals, work songs, field hollers, shouts, chants, and rhymed simple narrative ballads. The blues form, ubiquitous in jazz, rhythm and blues and rock and roll, is characterized by the call-and-response pattern, the blues scale and specific chord progressions, of which the twelve-bar blues is the most common. Blue notes (or "worried notes"), usually thirds, fifths or sevenths flattened in pitch are also an essential part of the sound. Blues shuffles or walking bass reinforce the trance-like rhythm and form a repetitive effect known as the groove.

Explanation culled from wikipedia

The patterns of words and rhythms of the blues was standardized in the

C. early 1900's

Explanation:

Rhythm and Blues is a musical genre born in the United States, it was developed in the 1920s and 1930s. In Chicago, Detroit, and New York City, by Jazz musicians that mixed rhythms and words to assemble a pattern that took form and became popular in African-American populations in the 1940s. To be marketed as Rythm and Blues. Some of its precursors were: Lonnie Johnson and Leroi Carl.