This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Q: The roots of hard rock can be traced back to the 1950s, particularly electric blues, which laid the foundations for key elements such as a rough declamatory vocal style, heavy guitar riffs, string-bending blues-scale guitar solos, strong beat, thick riff-laden texture, and posturing performances. Electric blues guitarists began experimenting with hard rock elements such as driving rhythms, distorted guitar solos and power chords in the 1950s, evident in the work of Memphis blues guitarists such as Joe Hill Louis, Willie Johnson, and particularly Pat Hare, who captured a "grittier, nastier, more ferocious electric guitar sound" on records such as James Cotton's "Cotton Crop Blues" (1954). Other antecedents include Link Wray's instrumental "Rumble" in 1958, and the surf rock instrumentals of Dick Dale, such as "Let's Go Trippin'" (1961) and "Misirlou" (1962).
A:
What genre laid the roots for hard rock?