the key phrase here is the following


oxalic acid, a substance that greatly impedes calcium absorption by the body

If we do have something that counteract the acid to absorb the calcium we have a solution

(A) Rice, which does not contain calcium, counteracts the effects of oxalic acid on calcium absorption.

Correct

(B) Dairy products, which contain even more calcium than spinach does, are often eaten by people who eat spinach on a regular basis.

Even if we do have more calcium we do not solve the problem of the absorption

(C) Neither the calcium nor the oxalic acid in spinach is destroyed when spinach is cooked.

This at most strengthen the argument

(D) Many leafy green vegetables other than spinach that are rich in calcium also contain high concentrations of oxalic acid.

Compound situation

(E) Oxalic acid has little effect on the body's ability to absorb nutrients other than calcium.

Other than calcium.....of

A is the answer
_________________

Replying to a private message to this question, which on line I found having to different OA: A and E. However E is wrong

Although spinach is rich in calcium, it also contains large amounts of oxalic acid, a substance that greatly impedes calcium absorption by the body.


Spinachs are rich in calcium but also a substance that at the same time impedes the calcium absorption

Therefore, other calcium-containing foods must be eaten either instead of or in addition to spinach if a person is to be sure of getting enough calcium.

So the conclusion is that we need OTHERS FOOD to eat together with spinach to have the calcium that spinach will not provide us. OTHER FOODS RICH IN CALCIUM

So the formula is the following : spinach (which in the end has ner-sero calcium) + other food that contains calcium= right amount of daily calcium dosage

(A)Rice, which does not contain calcium, counteracts the effects of oxalic acid on calcium absorption.

This is perfect to weaken the argument because it says that rice is food with NO calcium that is used in conjunction with spinach to eliminate the effect of oxalic acid without the usage of OTHER FOOD THAT HAS an additional dosage of calcium to integrate the spinachs

(E) Oxalic acid has little effect on the body's ability to absorb nutrients other than calcium.

This option does not weaken our way to obtain calcium because it just says that oxalic acid permits the absorption of other nutrients via the food. But we need something to optimize the calcium absorption. For now other nutrients is not our goal
_________________