Final answer:
Among the listed verbs, 'Poder' is the only one that is only irregular in the 'yo' (first person singular) form, being conjugated as 'puedo'. 'Tener', 'Decir', and 'Saber' have irregular 'yo' forms and other irregularities in their conjugations. The correct answer is option c.
Step-by-step explanation:
The question at hand revolves around identifying which of the following irregular Spanish verbs has an irregular form only in the 'yo' (first person singular) tense: Tener, Decir, Poder, and Saber. Upon examining the conjugation of these verbs in the present tense, we find that 'Tener' (tengo), 'Decir' (digo), and 'Saber' (sé) all have irregular 'yo' forms. However, 'Poder' is regular in the 'yo' form; it is conjugated as 'puedo', which follows an expected pattern of stem-changing verbs. Therefore, the correct option that is only irregular in the 'yo' form among the listed verbs is:
C) Poder
To elaborate further on the other verbs, 'Tener' changes to 'tengo' in the 'yo' form but the rest of the conjugations follow a regular -er pattern. Meanwhile, 'Decir' changes to 'digo' in the 'yo' form and has further irregularities in other forms (dices, dice, decimos, decís, dicen). Similarly, 'Saber' is irregular in the 'yo' form with 'sé', but its other forms follow a regular conjugation pattern (sabes, sabe, sabemos, sabéis, saben). Hence, as only 'Poder' maintains regularity aside from the 'yo' form, it is the correct option.