Fix m_arc choices (#1760)

* Update utils.py

This is a 4-choice task, option_e is null for all but 3 samples

* Fix options

Adaptive choices

* add option e

* bump multilingual arc version

---------
Co-authored-by: Hailey Schoelkopf <65563625+haileyschoelkopf@users.noreply.github.com>

lm_eval/tasks/okapi/arc_multilingual/_arc_yaml

@@ -20,4 +20,4 @@ metric_list:
     aggregation: mean
     higher_is_better: true
 metadata:
-  version: 1.0
+  version: 2.0

lm_eval/tasks/okapi/arc_multilingual/utils.py

@@ -4,8 +4,6 @@ import datasets
 
 
 def preprocess(text):
-    if text is None:
-        return " "
     text = text.strip()
     text = text.replace(" [title]", ". ")
     text = re.sub("\\[.*?\\]", "", text)
@@ -20,11 +18,15 @@ def process_docs(dataset: datasets.Dataset) -> datasets.Dataset:
             "id": doc["id"],
             "query": "Question: " + preprocess(doc["instruction"]) + "\nAnswer:",
             "choices": [
-                preprocess(doc["option_a"]),
-                preprocess(doc["option_b"]),
-                preprocess(doc["option_c"]),
-                preprocess(doc["option_d"]),
-                preprocess(doc["option_e"]),
+                preprocess(option)
+                for option in [
+                    doc["option_a"],
+                    doc["option_b"],
+                    doc["option_c"],
+                    doc["option_d"],
+                    doc["option_e"],
+                ]
+                if option
             ],
             "gold": ["A", "B", "C", "D", "E"].index(doc["answer"]),
         }