A. heating melting crystallization
b. weathering melting lithification
c. heating pressure crystallization
d. weathering deposition lithification

Referring to the diagram below which represents the complete rock cycle, we will find that:
Igneous rocks are converted to sedimentary rocks through two steps:
1- Igneous rocks undergo Weathering and erosion to form sediments
2- These sediments are then compacted and Lithified (cemented) forming the sedimentary rocks.

Based on the above, the best choice would be:
d. weathering deposition lithification