Final answer:
The correct loop to render section blocks in Liquid is {% for block in section.blocks %}, as it properly iterates through each block within the specified section.
Step-by-step explanation:
The correct for loop that would render section blocks in a templating language, such as Liquid which is commonly used in Shopify themes, is:
A) {% for block in section.blocks %}
This loop iterates through each block within a given section. Option B omits referencing 'section', which is needed to access the blocks within it. Option C is improperly formatted as a loop, and option D mistakenly swaps 'sections' and 'block', implying multiple sections inside a single block, which doesn't make sense in this context.