Which of the following is a kind of foliated metamorphic rock formed under directed pressure, where mineral grains are aligned in parallel layers or bands?

Introduction / Context:
This question belongs to geology and the study of metamorphic rocks. Metamorphic rocks can be foliated or non foliated depending on how mineral grains are arranged. Foliated metamorphic rocks show layering or banding as a result of pressure and temperature. The question asks which rocks in the list are examples of foliated metamorphic rocks.

Given Data / Assumptions:

• Slate, gneiss, and phyllite are among the options.
• Foliation refers to alignment of mineral grains into parallel planes or bands.
• We assume standard rock classification as taught in school level geology.

Concept / Approach:
Slate, phyllite, schist, and gneiss are classic examples of foliated metamorphic rocks. Slate forms from shale under low grade metamorphism and shows cleavage planes. Phyllite represents a slightly higher grade, with fine foliation and a silky sheen. Gneiss is a high grade metamorphic rock with coarse bands of light and dark minerals forming a banded appearance. Since all three examples listed are foliated metamorphic rocks, the answer is that all of the above are correct.

Step-by-Step Solution:

Verification / Alternative check:
Rock classification charts in textbooks list examples of foliated metamorphic rocks such as slate, phyllite, schist, and gneiss. They contrast these with non foliated rocks like marble and quartzite. Pictures show the foliated nature clearly. Seeing slate splitting into flat sheets, phyllite shining with fine layers, and gneiss with thick, alternating bands confirms that these are all foliated rocks.

Why Other Options Are Wrong:

• Saying only slate is a foliated rock is incomplete because gneiss and phyllite are also foliated.
• Saying only gneiss is foliated ignores the foliation present in slate and phyllite.
• Saying only phyllite is foliated also leaves out slate and gneiss. Only the all of the above option correctly groups all three.

Common Pitfalls:
Sometimes learners focus on only one familiar example of a foliated rock and forget that foliation can appear at different metamorphic grades. Learning the sequence slate to phyllite to schist to gneiss as progressively higher grade foliated rocks helps avoid this mistake. Another helpful tip is to remember that non foliated rocks like marble lack the obvious layering seen in these examples.

Final Answer:
All of the above